A leading professor in immunology has said that Jewish deaths due to coronavirus “undoubtedly could have been avoided" if social distancing measures had been introduced earlier.

Prof David Katz, emeritus professor of Immunopathology at University College London, told the JC there may have been more deaths because of the "Purim factor", as two weeks after the festival that saw "all sorts of social contact”,  there were many Jewish deaths.

He also told the JC that the current lockdown may last for “months not weeks” if the pandemic is to be brought under control.

Prof Katz – who is also executive chairman of the Jewish Medical Association and a member of South Hampstead Synagogue – acknowledged that Jews were initially overrepresented among deaths from coronavirus, accounting for around six per cent of the total.

But he pointed out this proportion was decreasing to be closer to the prorportion of the population who are Jewish, and suggested the initial higher proportion may have been because the disease's epicentre in Britain was in London.

"There were more [coronavirus cases] in London. There are more Jews in London," he said.

"Jews tend to be slightly older, the average age of Jews is slightly higher than the wider population, and older people are more susceptible to getting the severe forms of the disease and to dying.

“It has begun […] to be much closer to the proportion of Jews that there are in London.

“Every death is terrible and every death with this condition is not only terrible but it happens in a terrible way, and is very frightening and shouldn’t be happening.”

Regarding the lockdown, Prof Katz, 74, said: “Politicians don’t like saying that it’s going to be for six months; the uptake in the population would be much lower if you said it was an extended period of time.

“It’s very much months not weeks before one can turn around and say that these restrictions are not required.”

He also said that the antibody tests being suggested by the government – which show whether someone has already had the disease and developed immunity to it – were “hugely important at determining when you can relax these kinds of controls.

"At the end of the day, in six months’ time, can we allow people to start going back to cinemas and synagogues?”

But he warned that, in the acute phase of the illness, "when you’ve got your terrible acute respiratory syndrome and you’re rushed to hospital on a ventilator", antibody tests were "not that valuable.”

Last week Prime Minister Boris Johnson promised trials for a coronavirus vaccine “within a month”. But Prof Katz said it would likely be much longer.

He said: “The timescale of the development of a vaccine is much longer than people generally think...

"They would have to test [a potential vaccine], to give it to people that haven’t been infected if at all possible, and then, six months later, expose people to the same virus and these people, when they get the second exposure, would survive and wouldn’t get ill.

“Then, before that stage, you have to check safety. So you can’t give a vaccine that’s going to cause more problems than the disease, because the vaccine is unsafe.

“From other coronaviruses, the question of how long the immunity lasts for is a problem, because you can give the vaccine and it may be very useful for a short period of time, but eventually the vaccine has not been, if you like, strong enough to generate a long-lasting response."

Prof Katz noted that there was no vaccine for SARS or MERS, Covid-19's closest relatives, nor HIV.

"This is not to deny the importance of vaccines and vaccination, and it’s not to deny that people need to work on a vaccine because that is undoubtedly the best possible outcome," he said.

"But it’s to say it may take much longer than the period of time that’s been suggested.

“I might be totally wrong, but the more likely possibility is that we come up with some kind of drug combination […] that will actually work like the protease inhibitors have worked so well in HIV.

"So that route is probably the one that is more likely.”