The committee advising ministers on vaccine use in the UK will look “very carefully” at data surrounding the Johnson & Johnson version after the US recommended its rollout be paused.
The US is proposing a “pause” in administering the Johnson & Johnson Covid-19 vaccine to investigate reports of potentially dangerous blood clots.
Johnson & Johnson has since confirmed it will delay rollout of its single-dose vaccine across Europe following the review.
The UK has 30 million doses of the inoculation on order but it has not yet been signed off for use by the Medicines and Healthcare products Regulatory Agency (MHRA).
Professor Anthony Harnden, deputy chairman of the Joint Committee on Vaccination and Immunisation (JCVI), which advises ministers, noted the similarities between the Johnson & Johnson and Oxford/AstraZeneca jabs and promised to keep a “very close eye” on developments in the US.
Last week, the JCVI recommended it was “preferable” for adults aged under 30 with no underlying conditions to be “offered an alternative to the AstraZeneca” vaccine after reports of “extremely rare blood clots in a very small number of people”.
Prof Harnden told BBC Radio 4’s World At One: “The Johnson & Johnson vaccine of course is the same platform vaccine as the AstraZeneca, it’s an adenoviral vector platform vaccine, so I think this news is important and I think clearly they are experiencing (blood clot) cases in the United States and have paused that vaccine programme.
“We need to look at this data very carefully.”
Asked whether the decision in the US could impact UK deployment, Prof Harnden said the country had “millions” of doses of other vaccines.
He added: “What we will do is tailor the advice of vaccines accordingly to the data that we see, so this is emerging but we can’t make any decisions about Janssen (Johnson & Johnson) – it hasn’t been approved in this country yet – and obviously we will be keeping a very close eye on the American situation.”
In a joint statement, the US Centres for Disease Control and Prevention (CDC) and the Food and Drug Administration (FDA) said they were investigating clots in six women aged 18-48 that occurred six to 13 days after vaccination.
The clots occurred in veins that drain blood from the brain and occurred together with low platelets.
More than 6.8 million doses of the J&J vaccine have been administered in the US, the vast majority with no or mild side effects.
Downing Street said it would not “prejudge” the MHRA’s decision on the safety of the jab.
The Prime Minister’s spokesman said: “On Johnson & Johnson, it’s for the MHRA to make a ruling – obviously they are independent so I’m not going to prejudge their decision.
“It’s right that the independent safety watchdog looks at this and gives a ruling.”
Dr Peter English, a past chairman of the British Medical Association’s public health medicine committee, said: “This would appear to be a highly precautionary move by the US agencies.
“According to reports to date, there appear to have been six cases of central venous sinus thrombosis (CVST), in over 6.8 million doses of vaccine given.
“Even if all of the cases were caused by the vaccine, the risk of less than one in a million would have to be set against the benefits of protection from Covid-19 disease – a disease which, in itself, causes clotting in many cases.
“The call for a pause may dent confidence in vaccination.”