Although the the US intelligence community early on dismissed the notion that the coronavirus is a synthesised bioweapon, it is still weighing the possibility that the pandemic might have been touched off by an accident at a research facility rather than by an infection from a live-animal market, according to nine current and former intelligence and national security officials familiar with ongoing investigations.
After extensive research, scientists in the US and elsewhere have determined that the new strain of the coronavirus discovered in China in December is, as Chinese officials have maintained, of natural origin, but they are taking seriously that its route to human infection may have started in a lab in Wuhan.
"It's definitely a real possibility being bandied about at the high levels of the administration," said one of the sources, who has knowledge of China and national security.
"We are actively and vigorously tracking down every piece of information we get on this topic and we are writing frequently to update policymakers," an intelligence official told Yahoo News. The intelligence community "has not come down on any one theory."
Coronavirus across the globe
Coronavirus across the globe
Serbian army soldiers prepare a makeshift field hospital to accommodate patients infected by COVID-19 inside the Belgrade Arena, on July 6, 2020. - Serbia on July 2 restricted gatherings of more than five people in towns hit by a spike of coronavirus cases. After reining in its first outbreak of COVID-19 in early May, the Balkan state is now reporting a second surge with around 300 cases daily this week compared to around 50 or less a month ago. Since early June, the Balkan countries have a higher rate of infections, with up to more than 300 daily in Serbia. (Photo by Oliver BUNIC / AFP) (Photo by OLIVER BUNIC/AFP via Getty Images)
Serbian soldiers set up beds for the treatment of possible COVID-19 infected patients inside of the Belgrade Arena, in Belgrade, Serbia, Monday, July 6, 2020. Serbian authorities have declared an emergency in the capital Belgrade because of a surge in the new coronavirus cases. Emergency measures also have been introduced in several other towns in Serbia where hospitals have been overwhelmed by COVID-19 patients in recent days. (AP Photo/Darko Vojinovic)
FRANKFURT AM MAIN, GERMANY - JUNE 15: A staff member of the Balearic Islands Tourist Office holts a fakt sheeet for the tourists waiting to check in for a TUIfly flight to Mallorca at Frankfurt Airport on the first day that package tours are resuming since March during the coronavirus pandemic on June 15, 2020 in Frankfurt, Germany. The travellers are participating in a test project in which the Spanish government is allowing up to 11,000 tourists from Germany to travel to the Balearic Islands. Spain, which was hit especially hard by Covid-19, has begun to ease pandemic lockdown measures, though tourist travel is still restricted. The project is meant to test the viability of reopening the country to tourism. (Photo by Thomas Lohnes/Getty Images)
A woman waves San Fermin's red kerchief from a window as local police wear face masks as protection against coronavirus, on the day the ''txupinazo'' would usually take place to start the famous San Fermin festival, which was due canceled this year by the conoravirus, in Pamplona, northern Spain, Monday, July 6, 2020. (AP Photo/Alvaro Barrientos)
A resident, wearing white clothes and a traditional red scarf, looks out of her window on the day the ''txupinazo'' would usually take place to start the famous San Fermin festival, which was due canceled this year by the conoravirus, in Pamplona, northern Spain, Monday, July 6, 2020. (AP Photo/Alvaro Barrientos)
CORONAVIRUS: PLUS DE 1.000 DÉCÈS EN VINGT-QUATRE HEURES AU BRÉSIL
CORONAVIRUS: UN NOMBRE RECORD DE CONTAMINATIONS DANS LE MONDE EN UNE JOURNÉE
A calligraphist paints the name of Luz Maria Gonzalez onto the cross adorning her grave, as family members tidy the adjacent grave of her son 29-year-old son Francisco Javier, in the Municipal Cemetery of Valle de Chalco on the outskirts of Mexico City, Saturday, July 4, 2020. Gonzalez, 56, who had long suffered from asthma, diabetes, and hypertension, died two days after her son, who was hospitalized for breathing problems and a cough before dying of complications said to be related to pneumonia and undiagnosed diabetes. (AP Photo/Rebecca Blackwell)
An LGBTQ member prepares before a streamed performance of "Pride at Home," at the National Theatre in Caracas, Venezuela, Saturday, July 4, 2020. To celebrate 20 years of gay pride in Venezuela, LGBTQ members organized a presentation of different artistic shows via live streaming amid the new coronavirus pandemic. (AP Photo/Matias Delacroix)
The shadow of an LGBTQ member is reflected on the wall before a streamed performance of "Pride at Home," at the National Theatre in Caracas, Venezuela, Saturday, July 4, 2020. To celebrate 20 years of gay pride in Venezuela, LGBTQ members organized a presentation of different artistic shows via live streaming amid the new coronavirus pandemic. (AP Photo/Matias Delacroix)
A server wearing a mask checks orders for people in their cars watching the movie "Jumanji," Saturday, July 4, 2020, at Sacramento drive-in cinema in Asuncion, Paraguay. Several drive-in cinemas were started this weekend to aid in social distancing amid the coronavirus pandemic. (AP Photo/Jorge Saenz)
CORRECTS TO BROADWALK, INSTEAD OF BOARDWALK Tim Wirtz sits along the Hollywood Beach Broadwalk during the new coronavirus pandemic, Thursday, July 2, 2020, in Hollywood, Fla. In hard-hit South Florida, beaches from Palm Beach to Key West will be shut down for the Fourth of July holiday weekend. Restaurants and businesses along the Boardwalk will remain open. (AP Photo/Lynne Sladky)
A woman walks past benches taped off for social distancing outside a restaurant, Thursday, July 2, 2020, in La Habra, Calif. California's mood has gone from optimistic to sour as coronavirus cases and hospitalizations are on the rise heading into the July 4th weekend. Gov. Gavin Newsom has ordered bars and indoor restaurant dining closed in most of the state, many beaches are off limits, and he's imploring Californians to avoid holiday gatherings with family and friends. (AP Photo/Jae C. Hong)
A staff member talks to visitors to the Universal Studios Singapore theme park on the resort island of Sentosa in Singapore on July 3, 2020, as the attraction reopened after being temporarily closed due to concerns about the COVID-19 novel coronavirus. (Photo by Roslan RAHMAN / AFP) (Photo by ROSLAN RAHMAN/AFP via Getty Images)
Aspect of the La Boqueria market practically empty and without tourists, something unusual at this time of year in Barcelona, Spain on July 2, 2020. (Photo by Joan Valls/Urbanandsport /NurPhoto via Getty Images)
Aspect of the La Boqueria market practically empty and without tourists, something unusual at this time of year, in Barcelona, Spain on July 2, 2020. (Photo by Joan Valls/Urbanandsport /NurPhoto via Getty Images)
A tourist reacts as she arrives with others at Nikos Kazatzakis International Airport in Heraklion, Crete island, Greece, on Wednesday, July 1, 2020. The passengers most of them from Germany who came from Hamburg, with the first international flight to arrive in the island. Regional airports across Greece, including their tourist destination islands, began accepting direct international flights again on Wednesday, for the first time since flights were banned as part of the country's lockdown to prevent the spread of the coronavirus. (AP Photo/ Harry Nakos )
Tourists, arrive at Nikos Kazatzakis International Airport in Heraklion, Crete island, Greece, on Wednesday, July 1, 2020. The passengers most of them from Germany who came from Hamburg, with the first international flight to arrive in the island. Regional airports across Greece, including their tourist destination islands, began accepting direct international flights again on Wednesday, for the first time since flights were banned as part of the country's lockdown to prevent the spread of the coronavirus. (AP Photo/ Harry Nakos )
A man wearing a face mask and gloves to protect against coronavirus casts his ballot at a polling station in Moscow, Russia, Wednesday, July 1, 2020. The vote on the constitutional amendments that would reset the clock on Russian President Vladimir Putin's tenure and enable him to serve two more six-year terms is set to wrap up Wednesday. (AP Photo/Alexander Zemlianichenko)
Women wearing protective face masks pass an advertisement promoting awareness of the coronavirus outbreak at a shopping mall in Jakarta, Indonesia, Wednesday, July 1, 2020. The government of Indonesia's capital region is extending the first transition phase from large-scale social restrictions in Jakarta as the number of new confirmed coronavirus cases continues to rise. (AP Photo/Tatan Syuflana)
A woman, wearing a face mask and gloves to protect against coronavirus and observing social distancing guidelines, casts her ballot at a polling station with a portrait of former Soviet leader Josef Stalin on the wall in Volgograd, former Stalingrad, Russia, Wednesday, July 1, 2020. The vote on the constitutional amendments that would reset the clock on Russian President Vladimir Putin's tenure and enable him to serve two more six-year terms is set to wrap up Wednesday. (AP Photo/Dmitry Rogulin)
A woman, wearing a face mask to protect against coronavirus casts her ballot, observes social distancing guidelines, at a polling station in Grozny, Russia, Wednesday, July 1, 2020. Russia's vote on constitutional amendments that could allow President Vladimir Putin to extend his rule until 2036 entered its final day Wednesday amid widespread reports of pressure on voters and other irregularities. (AP Photo/Musa Sadulayev)
Spain's Prime Minister Pedro Sanchez gestures farewell to Portugal's Prime Minister Antonio Costa, right, as he departs after a ceremony to mark the reopening of the Portugal/Spain border in Elvas, Portugal, Wednesday, July 1, 2020. The border was closed for three and a half months due to the coronavirus pandemic. (AP Photo/Armando Franca)
People protest against Coronavirus trials in Africa, outside the University of the Witwatersrand in Johannesburg, South Africa, Wednesday, July 1, 2020. A protest against Africa’s first COVID-19 vaccine trial is underway as experts note a worrying level of resistance and misinformation around testing on the continent. (AP Photo/Themba Hadebe)
For demonstration purposes, an employee of the Centogene company takes a throat swab from a colleague at the airport in Frankfurt, Germany, Monday, June 29, 2020. In the future, people will be able to be tested for the corona virus within a few hours at Germany's first "Airport Corona Test" centre. (AP Photo/Michael Probst)
A security guard wearing a mask to curb the spread of the coronavirus watches over a gate in Beijing on Monday, June 29, 2020. Even as the world surpassed two sobering coronavirus milestones Sunday -- 500,000 confirmed deaths, 10 million confirmed cases -- and hit another high mark for daily new infections, China on Monday reported a further decline in new confirmed cases, with a total of just 12, including seven cases of domestic transmission in Beijing, where nearly 8.3 million people have now undergone testing in recent weeks. (AP Photo/Ng Han Guan)
A Greenpeace activists wearing protective gear to help curb the spread of the coronavirus arranges mannequins used to display posters during a protest outside the parliament in Jakarta, Indonesia, Monday, June 29, 2020. About a dozen of activists staged the protest against the government's omnibus bill on job creation that was intended to boost economic growth and create jobs, saying that it undermined labor rights and environmental protection. (AP Photo/Dita Alangkara)
An Indian man wearing a face mask as a precaution against the coronavirus sleeps outside closed shops during the reimposed lockdown in Gauhati, India, Monday, June 29, 2020. India has reported a new daily record of nearly 20,000 new infections as several Indian states reimpose partial or full lockdowns to stem the spread of the coronavirus. (AP Photo/Anupam Nath)
An Indian woman walks on a road painted with circles to help people maintain social distancing in Mumbai, India, Monday, June 29, 2020. Governments are stepping up testing and warily considering their next moves as the number of newly confirmed coronavirus cases surges in many countries. India reported more than 20,000 new infections on Monday. (AP Photo/Rajanish Kakade)
A sign on the door of the West Alabama Icehouse reads "Closed by the Governor", Monday, June 29, 2020, in Houston. Texas Gov. Greg Abbott shut down bars again and scaled back restaurant dining on Friday as cases climbed to record levels after the state embarked on one of America's fastest reopening. (AP Photo/David J. Phillip)
Empty tables are shown at the closed West Alabama Icehouse Monday, June 29, 2020, in Houston. Texas Gov. Greg Abbott shut down bars again and scaled back restaurant dining on Friday as cases climbed to record levels after the state embarked on one of America's fastest reopenings. (AP Photo/David J. Phillip)
A man wears a mask while voting, Monday, June 29, 2020, in Houston. Early voting for the Texas primary runoffs began Monday. (AP Photo/David J. Phillip)
A woman wearing a mask to curb the spread of the coronavirus holds her dog as they pass by a mall in Beijing on Monday, June 29, 2020. Even as the world surpassed two sobering coronavirus milestones Sunday -- 500,000 confirmed deaths, 10 million confirmed cases -- and hit another high mark for daily new infections, China on Monday reported a further decline in new confirmed cases. (AP Photo/Ng Han Guan)
A priest wearing a protective mask to avoid COVID-19 spread stands in St. Peter's Square during the Angelus prayer celebrated by Pope Francis from his studio window on the occasion of the Feast of Rome's Patrons Saints Peter and Paul, at the Vatican, Monday, June 29, 2020. (AP Photo/Riccardo De Luca)
Activists of Communist Party of India Marxist wearing face shields and hold placards during a protest asking the state government to increase testing and free treatment for all COVID-19 patients in Hyderabad, India, Monday, June 29, 2020. Governments are stepping up testing and warily considering their next moves as the number of newly confirmed coronavirus cases surges in many countries. India reported more than 20,000 new infections on Monday. (AP Photo/Mahesh Kumar A.)
Financial union members wearing face masks to help protect against the spread of the new coronavirus attend a rally against government's financial policy in front of the Financial Supervisory Service in Seoul, Monday, June 29, 2020. (AP Photo/Ahn Young-joon)
A roadside vendor sells mobile phone covers as she waits for customers at a closed market amid concerns over the spread of the COVID-19 coronavirus in Leh, the joint capital of the union territory of Ladakh, on June 28, 2020. (Photo by Tauseef MUSTAFA / AFP) (Photo by TAUSEEF MUSTAFA/AFP via Getty Images)
PARIS, FRANCE - JUNE 28: A man walks past electoral posters against Paris Mayor, Socialist Anne Hidalgo, who is fighting for a second term, as Parisians go to the polls today in the second round of Municipal elections on June 28, 2020 in Paris, France. The second-round vote, which was postponed by more than three months due to the coronavirus pandemic has forced candidates to conduct remote campaigns as restrictions have meant they were unable to canvas door to door, shake hands or distribute campaign material. (Photo by Kiran Ridley/Getty Images)
MELBOURNE, AUSTRALIA - JUNE 28: A general view of a pop-up Covid-19 testing tent during a COVID-19 testing blitz in the suburb of Broadmeadows on June 28, 2020 in Melbourne, Australia. Victoria's confirmed COVID-19 infection numbers continue to rise, with 49 new coronavirus cases recorded overnight. Health authorities are continuing on a testing blitz in Melbourne suburbs that have been identified as community transmission hotspots for coronavirus. Restrictions in Victoria have been tightened in response to the spike in new cases across the state with premier Daniel Andrews extending the current state of emergency for at least four weeks to allow police the power to enforce social distancing rules. (Photo by Asanka Ratnayake/Getty Images)
WARSAW, POLAND - JUNE 28: A father and son wearing protective face masks cast a ballot in the Polish presidential election during the coronavirus pandemic on June 28, 2020 in Warsaw, Poland. The two lead candidates are current Polish President Andrzej Duda of the socially conservative Law and Justice (PiS) party and Warsaw Mayor Rafal Trzaskowski of the of the centrist Civic Platform (PO). Today’s election to determine the next Polish president, who serves a five-year term, was originally scheduled for May but was delayed due to the coronavirus pandemic. (Photo by Sean Gallup/Getty Images)
Iran announced new measures to combat the spread of the novel coronavirus as the country counted 144 new fatalities, its highest death toll for a single day in almost three months (AFP Photo/ATTA KENARE)
TOPSHOT - Roadside vendors carry vegetables at a closed market amid concerns over the spread of the COVID-19 coronavirus in Leh, the joint capital of the union territory of Ladakh, on June 28, 2020. (Photo by Tauseef MUSTAFA / AFP) (Photo by TAUSEEF MUSTAFA/AFP via Getty Images)
A brig with scarlet sails on the Finnish Gulf coast during a rehearsal for the the Scarlet Sails festivities marking school graduation which will take place on June 27 in St.Petersburg, Russia, early Friday, June 26, 2020. This year the festival will not be held in the city center, but on the Finnish Gulf. Due to the coronavirus pandemic, there will be no spectators but the event will be broadcast on television. (AP Photo/Dmitri Lovetsky)
Sri Lankan Municipal health workers spray disinfectant to another colleague who conducted blood tests for COVID-19 antibody tests at a market place in Colombo, Sri Lanka, Friday, June 26, 2020. (AP Photo/Eranga Jayawardena)
A brig with scarlet sails travels on the Finnish Gulf coast during a rehearsal for the the Scarlet Sails festivities marking school graduation which will take place on June 27 in St.Petersburg, Russia, early Friday, June 26, 2020, with the setting moon in the background. This year the festival will not be held in the city center, but on the Finnish Gulf. Due to the coronavirus pandemic, there will be no spectators but the event will be broadcast on television. (AP Photo/Dmitri Lovetsky)
Tubers prepare to float the Comal River despite the recent spike in COVID-19 cases, Thursday, June 25, 2020, in New Braunfels, Texas. Texas Gov. Greg Abbott said Wednesday that the state is facing a "massive outbreak" in the coronavirus pandemic and that some new local restrictions may be needed to protect hospital space for new patients. (AP Photo/Eric Gay)
Staff of a cinema spray disinfectant at the cinema hall to prepare for reopening on July 1 in Kuala Lumpur, Malaysia, Friday, June 26, 2020. Malaysia entered the Recovery Movement Control Order (RMCO) after three months of coronavirus restrictions. (AP Photo/Vincent Thian)
Seguidores del Liverpool festejan con bengalas frente al estadio Anfield, el jueves 25 de junio de 2020, cuando el equipo se coronó en la Liga Premier con una victoria del Chelsea sobre el Manchester City (AP Foto/Jon Super)
People wearing face masks shop for accessories at a mobile shop in Hyderabad, India, Thursday, June 25, 2020. India is the fourth hardest-hit country by the pandemic in the world after the U.S., Russia and Brazil. (AP Photo/Mahesh Kumar A.)
A vendor wearing a face mask waits for customers under a flyover bridge in Hyderabad, India, Thursday, June 25, 2020. India is the fourth hardest-hit country by the pandemic in the world after the U.S., Russia and Brazil. (AP Photo/Mahesh Kumar A.)
A member of the election commission checks the temperature of a voter, both wearing face masks to protect against coronavirus at a polling station in Moscow, Russia, Thursday, June 25, 2020. Polls have opened in Russia on Thursday for a week-long vote on a constitutional reform that would allow President Vladimir Putin to stay in power until 2036. (AP Photo/Alexander Zemlianichenko)
Voters wearing face masks to protect against coronavirus stand in front of a ballot box, observing social distancing guidelines, at a polling station at a school in Moscow, Russia, Thursday, June 25, 2020. Polls have opened in Russia on Thursday for a week-long vote on a constitutional reform that would allow President Vladimir Putin to stay in power until 2036. (AP Photo/Alexander Zemlianichenko)
A Yemeni pharmacist wearing a protective face mask serves his customers behind a glass shield installed as a precautionary measure against the spread of the coronavirus at a pharmacy in Sanaa, Yemen, Thursday, June 25, 2020. (AP Photo/Hani Mohammed)
Senegalese students wear masks to curb the spread of the coronavirus as they return to classes on the first day back after more than three months away, at the Sacre Coeur college in Dakar, Senegal Thursday, June 25, 2020. (AP Photo/Sylvain Cherkaoui)
Senegalese students learn about health and the coronavirus during an English lesson as they returned to classes on the first day back after more than three months away, at the Sacre Coeur college in Dakar, Senegal Thursday, June 25, 2020. (AP Photo/Sylvain Cherkaoui)
Hospital workers demonstrate in front of the Robert Debre hospital, in Paris Thursday, June 25, 2020. French hospital workers are protesting to demand better pay and more investment in France's public hospital system, which is considered among the world's best but struggled to handle a flux of virus patients after years of cost cuts. (AP Photo/Christophe Ena)
Hospital workers demonstrate in front of the Robert Debre hospital, in Paris Thursday, June 25, 2020. French hospital workers are protesting to demand better pay and more investment in France's public hospital system, which is considered among the world's best but struggled to handle a flux of virus patients after years of cost cuts. Banner reads «Hospital workers. Users. All united for our health». (AP Photo/Christophe Ena)
Protesters wearing protective masks and maintaining social distancing attend a metalworkers demonstration asking for measures against economic crisis worsened by the Covid-19 pandemic, in Rome, Thursday, June 25, 2020. (AP Photo/Riccardo De Luca)
Police officers stop motorcyclists from entering a restricted area that is sealed off to control the spread of the coronavirus, in Lahore, Pakistan, Thursday, June 25, 2020. (AP Photo/K.M. Chaudhry)
People queue up prior to visit the Eiffel Tower, in Paris, Thursday, June 25, 2020. The Eiffel Tower reopens after the coronavirus pandemic led to the iconic Paris landmark's longest closure since World War II. (AP Photo/Thibault Camus)
WUHAN, CHINA - JUNE 25: (CHINA OUT) People wear face masks while uses a iPhone at the Auto Fair during Dragon Boat Festival holiday on June 25, 2020 in Wuhan, China. Since June 13 the response level of public health emergencies in Hubei Province has been reduced to level 3. Wuhan's health commission said that the city had no asymptomatic cases as of June 15, and there are no more close contacts under medical observation. (Photo by Getty Images)
Passengers travel wearing facemasks on a tram in Zagreb on June 25, 2020, as the wearing of masks on public transport in Croatia became mandatory on June 23, due to an increase of coronavirus infections after the relaxation of lockdown conditions. (Photo by DENIS LOVROVIC / AFP) (Photo by DENIS LOVROVIC/AFP via Getty Images)
MADRID, SPAIN - JUNE 25: The minister of Defense, Margarita Robles, is seen during the closing and recognition ceremony of the 'Balmis' operation, at the Retamares Base at the town of Pozuelo de Alarcón, on June 25, 2020 in Madrid, Spain. The 'Balmis' operation has been the largest military deployment in Spain in peacetime. During the last 98 days of state of alarm the military has carried out almost 20,000 interventions to combat Covid-19 in a total of 2,300 locations, throughout the territory. (Photo by Eduardo Parra/Europa Press via Getty Images) (Photo by Europa Press News/Europa Press via Getty Images)
Spain´s King Felipe VI (2R) and Queen Letizia (2L) walk at Palma Beach in Palma de Mallorca on June 25, 2020, during their national tour after the national lockdown to stop the spread of the novel coronavirus was lifted. (Photo by JAIME REINA / AFP) (Photo by JAIME REINA/AFP via Getty Images)
Dutch King Willem-Alexander visits Nedschroef in Helmond on June 25, 2020. - The visit focuses on the impact of the coronavirus crisis on the automotive industry. (Photo by Rob ENGELAAR / various sources / AFP) / Netherlands OUT (Photo by ROB ENGELAAR/ANP/AFP via Getty Images)
MOSCOW, RUSSIA - JUNE 24, 2020: A Russian soldier wears a face mask in Lenin Square during a Victory Day military parade marking the 75th anniversary of the victory in World War II. Victory Day parades across Russia have been postponed from 9 May to 24 June due to restrictions imposed to prevent the spread of the novel coronavirus. Kirill Kukhmar/TASS (Photo by Kirill Kukhmar\TASS via Getty Images)
Medics from Beijing Fengsheng Special Hospital of Traditional Medical Traumatology and Orthopaedics prepare for their shift at the Jinrong Street testing site, inside a room where a Communist Party flag and a piece of red tissue with words that reads "Beijing Fengsheng Special Hospital of Traditional Medical Traumatology and Orthopaedics" (back on wall) in Beijing on June 24, 2020. - China reported 12 new cases of COVID-19, including seven cases domestic cases in Beijing. (Photo by NICOLAS ASFOURI / AFP) (Photo by NICOLAS ASFOURI/AFP via Getty Images)
People leave a Costco outlet with a trolley full of toilet paper as fears of a second wave of COVID-19 have sparked a rush on some supermarket items in Melbourne on June 24, 2020. - Major supermarkets in the state of Victoria have reimposed buying limits on toilet paper and other essentials after a renewed escalation in demand sparked fears of a return to scenes of panic-buying seen early in the pandemic. (Photo by William WEST / AFP) (Photo by WILLIAM WEST/AFP via Getty Images)
VLADIVOSTOK, RUSSIA - JUNE 24, 2020: A woman takes a picture as WWII-era military hardware from the collection of the 20th Century Hardware in Primorsky Territory patriotic club takes part in a Victory Day military parade marking the 75th anniversary of the victory in World War II. Victory Day parades across Russia have been postponed from 9 May to 24 June due to restrictions imposed to prevent the spread of the novel coronavirus. Yuri Smityuk/TASS (Photo by Yuri Smityuk\TASS via Getty Images)
A woman reacts as she has her nasal swab sample collected by a health worker during a mass test for the new coronavirus at the local district office in Tanah Abang in Jakarta, Indonesia, Sunday, June 21, 2020. (AP Photo/Dita Alangkara)
Afghan yoga enthusiasts perform to mark International Yoga Day amid the COVID-19 pandemic lockdown, on the outskirts of Kabul, Afghanistan, Sunday, June 21, 2020. (AP Photo/Rahmat Gul)
Sergej Trifunovic, the leader of the Free Citizens Movement (PSG), an opposition party, casts his ballot for the parliamentary election at a polling station in Belgrade, Serbia, Sunday, June 21, 2020. Serbia's ruling populists are set to tighten their hold on power in a Sunday parliamentary election held amid concerns over the spread of the coronavirus in the Balkan country and a partial boycott by the opposition. (AP Photo/Marko Drobnjakovic)
A man wearing a mask as a precaution against coronavirus performs rituals at Sangam, the confluence of rivers the Ganges and the Yamuna during solar eclipse in Prayagraj, India, Sunday, June 21, 2020. (AP Photo/Rajesh Kumar Singh)
A lifeguard stand is decorated with a large mask to remind people to wear masks as precaution against the new coronavirus at a beach in Tel Aviv, Israel, Sunday, June 21, 2020. (AP Photo/Sebastian Scheiner)
People wearing face masks to protect against the new coronavirus take photos of a partial solar eclipse near the Forbidden City in Beijing, Sunday, June 21, 2020. (AP Photo/Mark Schiefelbein)
A man sits wearing a mask as a precaution against coronavirus as Hindu devotees perform rituals at Sangam, the confluence of rivers the Ganges and the Yamuna during solar eclipse in Prayagraj, India, Sunday, June 21, 2020. (AP Photo/Rajesh Kumar Singh)
A man, wearing a protective face mask, pushes a dolly filled with empty containers, as he and a child go in search of water in Caracas, Venezuela, Saturday, June 20, 2020, during a relaxation of restrictive measures amid the new coronavirus pandemic. (AP Photo/Ariana Cubillos)
Bride Jazmin Sanabria and her groom Joel Adorno, wearing protective face masks amid the new coronavirus pandemic, walk down the aisle in the first wedding ceremony since 101 days of quarantine at the Virgen del Rosario church, in Luque, Paraguay, Saturday, June 20, 2020. The government is easing restrictive measures, authorizing the opening of some stores, restaurants and churches that had been closed since March 10, as part of a plan coined, "Intelligent Quarantine." (AP Photo/Jorge Saenz)
Women buy vegetables through a protective plastic due to COVID-19, in a street market in Barranco neighborhood, in Lima, Peru, Saturday, June 20, 2020. (AP Photo/Rodrigo Abd)
People participate in an anti-government demonstration one week ahead of the presidential election in Warsaw, Poland, Saturday, June 20, 2020.(AP Photo/Czarek Sokolowski)
ISTANBUL, TURKEY - JUNE 18: Kid mannequins with masks are placed by the tables diagonally to protect customers' social distance as part of coronavirus (Covid-19) precaution at Beyoglu district in Istanbul, Turkey on June 18, 2020. (Photo by Emrah Yorulmaz/Anadolu Agency via Getty Images)
dpatop - 14 October 2020, Brazil, Sao Paulo: Cemetery workers in protective suits shoveling earth at the Vila Formosa cemetery in the Brazilian city of Sao Paulo in the middle of the Corona pandemic. Photo: Lincon Zarbietti/dpa (Photo by Lincon Zarbietti/picture alliance via Getty Images)
A member of a university laboratory wearing protective gear is pictured at a community health centre as the government collects swab samples from residents to test for the COVID-19 coronavirus in Banda Aceh on June 17, 2020. (Photo by CHAIDEER MAHYUDDIN / AFP) (Photo by CHAIDEER MAHYUDDIN/AFP via Getty Images)
Commuters have their temperatures checked as they arrive at the entrance to Hong Kong's Disneyland on June 17, 2020, a day before the theme park's doors reopen following nearly five months of closure in a fresh boost for a city that has largely managed to defeat the COVID-19 coronavirus. - It is just the second Disneyland around the world to resume services during the pandemic after Shanghai turned its lights and rides back on last month. (Photo by Anthony WALLACE / AFP) (Photo by ANTHONY WALLACE/AFP via Getty Images)
A waiter answers a client at La Coupole restaurant, Monday, June 15, 2020 in Paris. Paris is rediscovering itself, as its cafes and restaurants reopen for the first time since the fast-spreading virus forced them to close their doors March 14. Restaurants outside the Paris region opened earlier this month, and Paris cafes were allowed to serve people outside but not open their doors. After three months of losses, some restaurateurs fear it will take a long time for business to come back. (AP Photo/Christophe Ena)
BEIJING, CHINA - JUNE 16: A nurse wearing a protective suit and mask takes a nucleic acid test for COVID-19 from a person who either visited or lives near the Xinfadi Market at a testing facility at a Sport Center on June 16, 2020 in Beijing, China. From June 11 to June 16, Beijing reported a total of 106 new confirmed cases of coronavirus (covid-19), the number of new infection has risen after no new cases for nearly two months. (Photo by Lintao Zhang/Getty Images)
Cemetery workers wearing protective gear against the new coronavirus, walk after carrying the coffin of 72-year-old Monica Lagos to her grave at the Manantial cemetery in Santiago, Chile, Monday, June 15, 2020. According to her grandaughter Ninoska Vasquez, who works as an assistant at a health center, Lagos died from complications related to COVID-19. (AP Photo/Esteban Felix)
A commuter wearing a goggle and protective face mask to help curb the spread of the new coronavirus sits on the seat of a subway train in Beijing, Tuesday, June 16, 2020. China reported several dozen more coronavirus infections Tuesday as it increased testing and lockdown measures in parts of the capital to control what appeared to be its largest outbreak in more than two months. (AP Photo/Andy Wong)
BOGOTA, COLOMBIA - JUNE 12: A personnel wears a face shield as a preventive measure against the coronavirus (COVID-19) pandemic at the Hayuelos Mall in Bogota, Colombia, on June 12, 2020. After almost 3 months of imposing the semi-lockdown regulations to curb the spread of coronavirus, the Colombian government started the transition to new normal with opening offices, shopping malls, and other places on conditions of following health protocols and maintaining social distance. (Photo by Juan Jaiver Torres Padilla/Anadolu Agency via Getty Images)
A German tourist takes a sunbath at the Riu Concordia hotel swimming pool in Palma de Mallorca, Spain, Monday, June 15, 2020. Borders opened up across Europe on Monday after three months of coronavirus closures that began chaotically in March. But many restrictions persist, it's unclear how keen Europeans will be to travel this summer and the continent is still closed to Americans, Asians and other international tourists. (AP Photo/Joan Mateu)
Workers walk across a banquet hall which is generally used for weddings that has been converted to makeshift coronavirus hospital as the Indian capital struggles to contain a spike in cases. in New Delhi, India, Monday, June 15, 2020. India is the fourth hardest-hit country by the COVID-19 pandemic in the world after the U.S., Russia and Brazil. (AP Photo/Manish Swarup)
A student arrives at school for the first day of class since the lockdown to curb the spread of the new coronavirus pandemic in Montevideo, Uruguay, Monday, June 15, 2020. Some children in urban areas returned to school Monday. (AP Photo/Matilde Campodonico)
15 June 2020, Yemen, Sanaa: Medical workers talk while checking on patients in the intensive care unit of a hospital, where coronavirus (Covid-19) patients are treated. Photo: Hani Al-Ansi/dpa (Photo by Hani Al-Ansi/picture alliance via Getty Images)
Discover More Like This
BACK TO SLIDE
While Chinese officials were quick to link the origin of the disease to infected animals at the Wuhan Seafood Market, which was formally closed on Jan. 1, scientists have not traced the initial exposure back to any specific animals. Therefore, an alternative possibility remains — that a natural virus sample being studied at a research laboratory in Wuhan infected a researcher who spread it in the community, or it escaped via hazardous waste or a lab animal.
There are reasons to be wary of that theory. It may serve as a propaganda tool for politicians who want to fan tensions with China, and many scientists still argue that a natural outbreak is the most likely possibility, dismissing any alternative theory. But finding the source of the outbreak could also be vital in understanding how it spread and how to prevent the next potential pandemic.
In December, Chinese health officials began to publicly worry that the mysterious cluster of pneumonia patients in Hubei province might be a sign of something ominous. On Dec. 31, the Wuhan Municipal Health Commission formally notified the World Health Organisation's country office in China about the worrying trend.
Since those initial reports, more than a million people around the world have tested positive for the new, highly infectious strain of coronavirus and its resulting disease, Covid-19. More than 100,000 have died.
According to multiple news outlets, the intelligence community was gathering information on the outbreak as early as November. By the new year, the White House was being briefed on the potential that the virus would spread globally. Chinese officials were hiding some of the details, intelligence officials said, but they feared things could get much worse. President Trump, however, waited until March to recommend nationwide extreme social distancing measures to slow the outbreak.
While the severity of the potential pandemic wasn't understood back in November and early December, sources tell Yahoo News there has been intense internal interest in the source of the outbreak. While the intelligence community is not discounting a range of potential transmission vectors, including contact between humans and animals, officials are seriously pursuing the possibility that a natural sample of the virus escaped a laboratory.
"It's absolutely being looked at very closely at the highest levels," said one intelligence source with knowledge of the investigations. The British government is reportedly considering the same possibility.
One reason for the suspicion is the lack of information coming from China. Beijing's quick denials of involvement, and the decision to immediately identify the Wuhan Seafood Market as the source, raised eyebrows among some US intelligence officials.
"I find it very funny that China very quickly blamed the market," said one recently retired intelligence official.
The Chinese government did not respond to multiple requests for comment made through its foreign ministry and its embassy in the US.
In fact, some of the very first cases of Covid-19 were not linked to the market, and there are a number of important research institutions in Wuhan where infectious diseases are studied.
Those include the Wuhan National Biosafety Lab, the first publicly acknowledged lab with the highest biosafety standards; the Wuhan branch of the Chinese Centers for Disease Control and Prevention; and the Wuhan Institute of Virology, home to one of the world's top research groups on bat coronaviruses, where scientists have studied thousands of samples.
The Wuhan Institute of Virology, which collaborates with researchers and institutions around the world, including the US National Institutes of Health, is a key site for the Global Virome Project, a global initiative focused on preventing the next pandemic by researching DNA and RNA of viruses in animals that could potentially infect humans. While that group does not typically work with intact virus samples, according to David Relman, a microbiologist at Stanford University, "it is possible" that the researchers could have collected a virus sample from a bat and been researching it within the lab.
The new virus's genome most closely resembles a bat coronavirus discovered in July 2013 in Yunnan province in China, information made public by the Wuhan Institute of Virology only on Jan. 23 of this year. The progenitor of the current virus, says Richard Ebright, a molecular biologist at Rutgers University, could be either the 2013 bat sample or another bat coronavirus that is closely related and hasn't been discovered or disclosed as of today.
Not all scientists agree with this possibility. Writing in Nature, a team of five scientists argued that the new virus, SARS-Cov-2, emerged too recently to have been identified, isolated from other virus samples, cultured and then accidentally released from a lab. Because there is so much variety in types of coronavirus in bats and other species, virus specimens are "massively under-sampled," wrote the authors, making it less likely Chinese researchers discovered this specific strain. "We do not believe that any type of laboratory-based scenario is plausible," they concluded.
However, even Chinese researchers initially pointed to the possibility of a lab accident in a study published in February on ResearchGate. "The killer coronavirus probably originated from a laboratory in Wuhan," wrote researchers — although they also raised the possibility of natural transmission. "Safety level may need to be reinforced in high risk biohazardous laboratories," continued Botao Xiao and Lei Xiao of Guangxhou's South China University of Technology. Botao Xiao later withdrew the paper, telling the Wall Street Journal he did not have evidence for his theories.
Two Chinese universities recently posted online notices placing restrictions on publishing academic research on the origins of the coronavirus, though those have since been removed from the internet.
Public videos and articles have revealed poor safety standards on the part of some Wuhan researchers, including being exposed to bat urine and failing to wear proper protective equipment. Additionally, there have been incidents of SARS samples escaping from Chinese labs in the past.
Retired Air Force Brig. Gen. Robert Spalding, a senior fellow at the Hudson Institute and a former National Security Council official who worked on China issues in the Trump administration, told Yahoo News he believes a lab accident is a "definite possibility."
"They have had prior accidental releases of the SARS virus. Also it seems the bats were not local to Wuhan. I do not know if the US government is looking into this," he wrote in an email. But if the Wuhan National Biosafety Lab scientists were dabbling in potentially dangerous research, "Beijing would not want to call attention to [it]," he concluded.
Zheng-Li Shi, who leads the group studying bat coronavirus samples at the Wuhan Institute of Virology, published a paper in 2016 in the Journal of Virology detailing experiments on two bat coronaviruses with features needed for human infections. According to the paper, the scientists maintained biosafety level two standards while conducting the research, which is in line with the international standards for coronavirus samples except for SARS and MERS.
There are four different biosafety levels. Level four is reserved for the most dangerous and infectious diseases, such as Ebola. Under biosafety level two, samples are considered "moderate-risk," according to the CDC, leading to minimal requirements for hand-washing sinks, automatically locking doors and methods to decontaminate waste.
Those standards may have been inadequate for coronavirus samples, experts argue.
"Virus collection, culture, isolation, or animal infection at BSL-2," given the infectiousness of the coronavirus, "would pose a high risk of accidental infection of a lab worker, and from the lab worker, the public," wrote Ebright in an email to Yahoo News.
Ebright is one of many scientists who have pushed the global community to improve its handling of dangerous pathogens, a problem not just for China but for labs worldwide. USA Today in 2015 conducted a wide-ranging investigation of accidents, safety violations and potential disasters in US labs, and found problems ranging from infected lab mice escaping to failures with protective gear.
Relman, who has advised the government on emerging infectious diseases, told Yahoo News that whether the virus escaped from a lab or not — something he personally views as less likely — he hopes the pandemic will spur higher lab safety standards worldwide. "Standards are not clear enough, not uniformly practiced, and are not keeping up with advances in biological technologies — which, in theory, allow many more people to experiment with these viruses," he wrote.
The possibility that the pandemic originated in a lab was first discussed publicly in mid-February as China hawks and Trump allies began to push the bioweapon angle. The New York Times reported that the main proponent of the lab accident theory is President Trump's deputy national security adviser, Matthew Pottinger, a former Wall Street Journal reporter in China with a reputation for hawkish views on Beijing. Pottinger, through an NSC spokesperson, declined to comment.
Republican Sen. Tom Cotton of Arkansas publicly promoted a range of theories, including that the virus could have been a "deliberate release" or an "engineered bioweapon" that was accidentally leaked. However, Cotton, who sits on the Senate Intelligence Committee, also noted that the culprit could have been "good science, bad safety" or a mistake made in the course of honest research on "diagnostic testing or vaccines."
Current and former intelligence officials familiar with internal briefings declined to provide details but noted the lab accident theory being promoted by Cotton may not be so crazy. "Tom Cotton is presenting some useful stuff there," said one recently retired intelligence official when asked about the theory.
Another former intelligence official in touch with current officials told Yahoo News that Trump began calling the virus the "Wuhan virus" after intelligence briefings he received on its origin. Critics said this term, which is not used by the scientific community, was bolstering xenophobic attacks on Asian-Americans and Asians worldwide at a time when international cooperation is required to investigate the outbreak.
The possibility that the virus leaked during a lab accident "is being seriously considered" within the US government, according to another recently retired senior national security official, who pointed to the State Department's 2019 compliance report on arms control, nonproliferation and disarmament. The report notes that Chinese officials have failed to reassure inspectors they are obeying the Biological Weapons Convention, including by not providing information about research on "numerous toxins with potential dual-use application."
The State Department did not respond to requests for comment on whether compliance concerns extend to potential lab accidents of dangerous virus samples. But in late March, Yahoo News reported that the FBI detected samples of the SARS virus and flu in Chinese scientists' luggage, presenting a "biosecurity risk" for both deliberate acts of terrorism and potential accidents during research.
According to the Washington Post, US State Department employees visited the Wuhan virology lab in 2018 and sent a cable back home listing safety concerns about the lab's bat coronavirus studies. Similar concerns were presented about the Wuhan National Biosafety Lab in 2017, though writers at the prestigious scientific journal Nature have since appended a notice arguing that their reporting on past safety concerns should not be used as evidence that a lab accident led to the 2020 pandemic.
Sources declined to discuss any evidence, if it exists, that points to a potential lab accident, but the intelligence community is not ruling it out.
"Absent a credible whistleblower or verified primary communication intercept, it will not be possible to prove the origins with certainty," said Relman, the Stanford microbiologist. "However, with more relevant data, the likelihood of a natural virus versus accidental origin can be strengthened or diminished."
One former senior CIA official said that if the virus did originate from a Chinese research institution, the US intelligence community will eventually be able to prove it. "There will be disaffected Chinese sources," the former official said.
"Disasters are good for us," the former CIA official continued. "The crappier the regime, the better it is to recruit sources there."