There hasn’t been enough research on how much protection a fourth dose can offer, medical professionals told CNBC.
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Countries are beginning to offer a fourth dose of the Covid-19 vaccine to vulnerable groups, but medical professionals are undecided on whether it would benefit the wider population.
The U.S. Food and Drug Administration has so far authorized a fourth shot only for those aged 50 and above, as well as those who are immunocompromised. And the U.S. Centers for Disease Control and Prevention was skeptical of the need for a fourth dose for healthy adults in the absence of a clearer public health strategy.
Those decisions came as a study from Israel found that although a fourth dose of the Pfizer-BioNTech vaccine offers protection against serious illness for at least six weeks after the shot, it provides only short-lived protection against infection, which wanes after just four weeks.
No ‘good evidence’ yet
The medical consensus so far is that there hasn’t been enough research on how much protection a fourth dose can offer.
The World Health Organization hasn’t given an official recommendation on a fourth dose, and “there isn’t any good evidence at this point of time” that it will be beneficial, said WHO chief scientist Soumya Swaminathan.
“What we know from immunology is that if you give another booster, you will see a temporary increase in the neutralizing antibodies. But what we’ve also seen is that these neutralizing antibodies will wane quite rapidly,” Swaminathan told CNBC in an interview.
A fourth dose doesn’t really do much of anything … I’m not sure we need to get out and just jump up and down screaming that everybody needs to get aboard.
Paul Goepfert
professor at the University of Alabama
“This happened after the third dose. And it’s happened again after the fourth dose,” she added.
Paul Goepfert, professor of medicine at the University of Alabama, shared that view, saying that “a fourth dose doesn’t really do much of anything … I’m not sure we need to get out and just jump up and down screaming that everybody needs to get aboard.”
Since the study from Israel shows the fourth dose can provide protection against serious disease, countries such as Israel, Denmark and Singapore have made a second booster shot available to high-risk groups.
“Rather than saying that the protection wanes, I would say that this boost effect is strongest shortly after the vaccine was administered, but that it remains protective overall,” said Ashley St. John, an associate professor at Duke-NUS Medical School.
“Importantly there was no waning of protection against severe disease, which is the most key effect of vaccination we aim to achieve,” she added.
Annual booster shots?
Questions are being raised over the need for more booster shots as the emergence of more Covid variants may require more targeted vaccines.
Anthony Fauci, White House chief medical advisor, told NBC News in January that people may need to get booster shots every year or two.
However, blanket vaccine approaches may not continue to work.
It is possible that high-risk groups — such as the elderly — may need an annual vaccine, said Swaminathan. But “it’s not…
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