For those hoping that it would be third time’s a charm for the Covid-19 vaccines, things have recently become rather more complicated.
On Tuesday night, Israeli scientists – early movers on vaccines throughout 2021 – said some vulnerable groups may now need a fourth jab to remain fully protected in the face of the new omicron variant. Germany made a similar announcement the following day.
The countries have slightly different approaches. Israel is set to stick to Pfizer for its booster campaign for the over-60s, the clinically vulnerable and healthcare workers, and it is unclear yet whether the jab will be recommended, or merely offered. Germany is ordering the omicron-specific jab from Pfizer, which is still in development, as well as the newly approved Novavax and Valneva jabs.
For an NHS currently stretched to its limits and beyond with an accelerated third dose booster campaign on top of rising omicron case numbers, a fourth dose may tip it over the edge – particularly as Israel is set to offer a fourth dose just four months after the third. The British public may feel the same.
And global health experts the world over despair over the growing gulf – while richer countries are discussing fourth doses, only 12 per cent of people in Africa are vaccinated.
But is a fourth dose actually necessary?
Israeli scientists certainly think so, and are already sharing their conclusions globally, including with public health bodies in the UK and US.
Prof Nadav Davidovitch, the director of the School of Public Health at Ben Gurion University and a member of Israel’s Pandemic Expert Committee, said the committee reviewed evidence on Wednesday in a pre-print that showed waning immunity several months after people received a third dose.
“We are seeing waning immunity, reflected in the reduction of antibodies and also in breakthrough infections, in people that got the third dose. It's a bit similar to the situation with the second dose several months ago,” he told The Telegraph.
“Due to this, some of us thought that those who are more than four months after their third dose ought to be vaccinated."
In the summer, Israel was among the first to give a third booster. Other countries were not convinced, and prevaricated – including the UK – before eventually following suit. Arguably, this delay cost lives.
Prof Davidovitch says Israel is better at making decisions based on early indications, rather than the gold-plated evidence that UK officials have sometimes looked for before making a call.
“I think Israel is much more used to making decisions during emergencies, better at decisions under pressure,” he said. “Very soon, we are going to face a huge wave of omicron... For high-risk groups, there is the risk that many of them will suffer from severe illness or even death. It's not clear yet, but this is not something you can just wait and see.”
He also advocates focusing on getting the initial doses into more of the population and upping other measures, like mask wearing, to tackle omicron.
Other scientists said they had not yet seen enough evidence to back fourth doses, and some were cynical about big pharmaceutical companies claiming they were needed – Pfizer’s chief executive said as much earlier this year.
Prof Lawrence Young, a virologist at the University of Warwick, said: “I’m not aware of any evidence supporting the need, value and efficacy of a fourth dose of vaccine.”
He said immunity would be expected to wane, particularly in the elderly and most vulnerable, but this did not necessarily mean fourth doses would be needed – boosters may continue to protect against the most important risks – severe disease, hospitalisation and death – longer-term.
Already, data has shown that the protection offered by vaccines is better at preventing serious illness than infection in the long-term: for example, the WHO suggests effectiveness against severe disease waned by about eight per cent, six months after the first course of jabs. For symptomatic disease of any kind, effectiveness decreased by 32 per cent for those over 50 in the same period - although this data pre-dates omicron.
As such, the WHO still calls for a moratorium on boosters for healthy people before more of the rest of the world gets access to a vaccine, which is something the other scientists said was important, too.
On Wednesday, Dr Tedros Adhanom Ghebreyesus, head of the WHO, warned again that cross-population boosters would actually prolong the pandemic, adding that supporting all countries to reach 40 per cent of their population vaccinated was a far better plan.
“No country can boost its way out of the pandemic,” he said.
Other questions remain.
These include whether giving a mix of vaccines rather than just one jab – Israel has almost exclusively used Pfizer’s vaccine – could offer longer lasting protection.
It also remains to be seen if boosters will have to be administered regularly for the long-term. Four in little over a year is already highly unusual, experts said; as Sir Jeremy Farrar, director of the Wellcome Trust and a former government advisor, pointed out on Twitter, it may be time for a re-think.
“Fourth vaccine in little over a year. Real issue on supply if other countries follow,” he wrote. “Need to invest at scale [in] 2nd & 3rd generation vaccines- safe & effective & give long lasting, broadly sterilising immunity. A huge scientific challenge. One we must meet.”
For Prof Davidovitch, that is a question for the future. Early data on declining protection, and the rise of omicron, required a quicker answer – the kind Israel has specialised in.
“Allowing people who are maybe 75 living in elderly care that want to be vaccinated with a fourth dose after four months - I don't think you can deny them," he said.
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