Herd immunity not likely for the foreseeable future – expert


Herd immunity is not going to be possible for the foreseeable future despite the imminent rollout of a coronavirus vaccine, an expert has warned.

Independent Sage member Professor Gabriel Scally said that while a vaccine would make a “big difference”, it is not going to be the whole solution.

The president of the epidemiology and public health section at the Royal Society of Medicine explained that a lot is unknown about the Pfizer/BioNTech vaccine which has been approved by the Medicines and Healthcare products Regulatory Agency (MHRA).

Covid-19 growth rates
Covid-19 growth rates

Prof Scally explained that it was not trialled on children or pregnant women, and that we do not know the overall effectiveness of the vaccine when delivered in the population.

Some experts estimate a Covid-19 vaccine will need to be accepted by at least 55% of the population to provide herd immunity while others suggest even higher numbers will be needed.

Speaking at an Independent Sage briefing, he said: “I personally don’t think we should be talking at all about herd immunity.

“For a whole string of reasons, I think herd immunity is not going to be possible for the foreseeable future.

“I think we need to concentrate on the realistic scenario – the vaccine is great, it’s going to make a big difference but it’s not going to be the whole answer.”

He added: “That’s one of the stories of Covid-19 – there is no silver bullet.

“We need all of the tools to reduce the prevalence of the virus that we can possibly deploy and the vaccine is absolutely one of them.”

How the Pfizer/BioNTech vaccine works
How the Pfizer/BioNTech vaccine works

Anthony Costello, a professor at University College London, said the data suggests it is inevitable there will be a surge in cases again before the year is over.

He said: “The positivity rate is still above the WHO threshold of 5% where they say you should take very strong measures to bring them down.

“So I think it’s inevitable we’re going to surge again, probably by Christmas and New Year.”

He added that every member of Independent Sage would get vaccinated and that the panel supports the vaccines.

Sir David King, the chair of Independent Sage, offered his support to the MHRA, which has received some criticism from the international community due to the pace at which it approved the vaccine.

Sir David said: “This is our national drug regulatory body and the MHRA has a substantial international record.

“They would not be putting that record at risk under any sort of pressure from the Government.

“I’m really sure that these are people of integrity who will understand the nature of this particular pandemic and the reason they had to move quickly. But, I have to say, that I think we can trust their word on this.”