As the Delta variant is rapidly spreading around the world, the prospect of a third “booster” injection is gaining interest even in countries where a high proportion of people have been vaccinated.
Experts say it is too early to know for sure whether countries should organize a third round of vaccination later in the year. Some suggest that priority should be given to hundreds of millions in the south of the world who have not even received their first shot.
Earlier this month, manufacturers Pfizer/BioNTech said they would seek permission from US and European authorities to provide a third dose of their vaccine.
They said this was aimed at ensuring stronger immunity in individuals than that conferred by two doses.
The developers said two doses of their vaccine protected against severe Covid-19 for at least six months.
But faced with emerging variants, they said they expected some decline in efficacy over time.
White House chief medical adviser Anthony Fauci said on CNBC Tuesday that Pfizer/BioNTech’s third dose application “was an appropriate preparation[for]the possibility that you might need a booster.”
“But if you translate that into, ‘We need a booster, everyone gets a booster,’ then that’s not appropriate,” Fauci said.
He added that there are still too many people who are not fully vaccinated with two doses, let alone three.
– What do the authorities say?
There is currently no sign that medical authorities will recommend a third dose for anyone who has already received two.
The European Medicines Agency and the European Center for Disease Control say it is too early to say whether a third dose is needed.
“There is not yet enough data from vaccination campaigns and ongoing studies to understand how long the protection against the vaccines will last, also given the spread of variants,” they said in a joint statement.
Didier Houssin, director of the World Health Organization’s emergency committee, said he didn’t believe there was enough evidence to recommend a third dose at this point.
He also warned that talking about a third dose could “raise concerns about vaccine access” at a time when only a small percentage of people have been fully vaccinated in most countries.
Hungarian President Viktor Orban said on Friday that some citizens will have access to a third injection from early August.
Hungary has largely been alone in vaccines, with widespread use of Chinese and Russian injections instead of the brands approved by Moderna, Pfizer/BioNTech, AstraZeneca and Johnson & Johnson for use in the EU.
– Useful for vulnerable people?
While mass third-dose campaigns don’t seem to be in the offing, several countries have already started giving third doses to certain people.
These include individuals with weakened immune systems, including those who have had organ transplants, or who suffer from cancer or kidney problems.
Of these, the body’s natural immune response to pathogens is suppressed, meaning the immune response triggered by vaccines may be less potent.
Israel, along with France, has started giving third doses to certain people this week.
“Recent data showed that the immune response elicited by two doses was insufficient in severely immunosuppressed subjects,” the French Vaccine Commission said in May.
Israel, for its part, justified its decision by pointing to “a large number of cases in recent weeks” and the risk to immunocompromised patients.
– Or the elderly?
France went a step further on Monday by announcing that a “booster campaign” would start from September for people who have been fully vaccinated early in the year.
The vaccination board said earlier this month it was starting its third dose drive with people over 80.
“Scientific data to support this proposal is still limited, but taking into account studies showing a decline in antibody levels in this population, and the potentially serious impact on the health care system, it seems reasonable,” the council said.
It added that it was possible that younger people could eventually have access to a third injection, depending on how the pandemic progresses.
(Except for the headline, this story has not been edited by NDTV staff and has been published from a syndicated feed.)