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Explained: Implications of Israel’s nod to a booster shot of Pfizer vaccine

In Israel, some elderly people have started getting a third dose of the Pfizer vaccine against Covid-19. Why are booster shots being administered, and are there any objections to a third dose?

Israel, Pfizer, third doseA health worker takes a swab sample from a woman in Binyamina, Israel (AP)

Israel has started administering the third dose of Pfizer-BioNTech’s Covid-19 vaccine to elderly people with compromised immune systems. However, in the United States, officials, after a meeting with Pfizer’s chief scientific officer on Monday, said more data would be required to determine whether a third dose of the vaccine would be necessary. The twin developments come at a time when there are increasing concerns about breakthrough infections in fully vaccinated people and intense debates over the necessity of a booster shot.

Why has Israel started administering booster doses?

Israel’s decision to roll out booster shots to elderly and immunocompromised people with underlying health conditions comes amid reports of rising breakthrough infections. Comparing datasets on vaccinated people, taking into consideration the numbers from Israel Health Ministry and Pfizer’s own laboratory data, threw up an important point of convergence — there is enough proof to suggest that immunity in fully vaccinated people is waning after six to eight months, the New York Times reported.

There are also reports of the elderly people, who were the earliest to get vaccinated, being more infected now.

The country has released a list of types of people eligible to get the booster shot, with priority being given to heart, lung and kidney transfer recipients and also others with weak immune conditions, including cancer patients. Israel now hopes to administer booster shots to these groups of people to shore up their immunity and prevent more breakthrough infections.

Although Israel had one of the world’s fastest vaccine rollouts, with 57% of its population having received both jabs till now, the country has reported a surge in recent times. The number of daily infections in the country has risen from single digits a month ago to an average of 452 cases a day. The spike coincides with increased transmission of the Delta variant, which is responsible for over 90% of the cases, and reports of reduced effectiveness of the Pfizer vaccine against the variant.

Recent data by the Israel Health Ministry stated that the effectiveness of the Pfizer-BioNTech vaccine dropped in recent weeks, offering only 64% protection against infection even after two doses. It is, however, 93% effective in preventing hospitalization, the data shows. Recent research by Hebrew University found that the Pfizer vaccine was 70% effective against Delta.

However, Ran Balicer, chairman of the national expert advisory team on Covid-19 response, in an interview with Bloomberg Television, had earlier said that there is no conclusive evidence yet to suggest that immunity is waning in fully vaccinated people and there can be other reasons for the spike in infections. Cases are rising now because restrictions have been lifted and people are not following Covid norms, he had said, adding “We do feel we have a high level of uncertainty of where this wave might stop if we take a laissez-faire approach.”


What is Pfizer’s take on a booster shot for its vaccine?

Pfizer-BioNTech, in a statement released last week, said that they are working on a version of their vaccine which would specifically target the Delta variant. Though the data has not been peer-reviewed or published yet, their study also shows a significant spike in antibodies if a booster shot is administered within six months of the second dose. Pfizer also said that it would submit the data to the US FDA soon.

Stating that the effects of the two doses fade over time, Pfizer said that “a third dose may be needed within 6 to 12 months after full vaccination”. The company also underlined that their studies have shown a five- to 10-fold jump in antibody levels after the third dose, as compared to their second dose months earlier.

Pfizer CEO Albert Bourla had also said earlier that people are “likely” to need a booster shot which will be necessary to “maintain highest levels of protection”.

Why are US officials reluctant to give the nod?


After Pfizer said that a booster dose offers “the highest levels of protection”, the US FDA and Centres for Disease Control and Prevention released a statement arguing that people “do not need a booster shot at this time” and people who are unvaccinated should “get vaccinated as soon as possible to protect themselves and their community.”

The statement further said, “FDA, CDC, and NIH are engaged in a science-based, rigorous process to consider whether or when a booster might be necessary. This process takes into account laboratory data, clinical trial data, and cohort data – which can include data from specific pharmaceutical companies, but does not rely on those data exclusively. We continue to review any new data as it becomes available and will keep the public informed.”

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Lending support to the statement, National Institute of Allergy and Infectious Diseases Director Dr. Anthony Fauci told CNN, “We respect what the pharmaceutical company is doing, but the American public should take their advice from the CDC and the FDA. The message is very clear: the CDC and the FDA say if you have been fully vaccinated at this point in time, you do not need a booster shot.”

After the high-level online meeting, in which Pfizer’s scientific officer virtually briefed top doctors in the US federal government, officials reportedly said there is not enough data at this moment to give nod to a booster shot. They further pointed out that more research, possibly spanning several more months, could be required to arrive at the decision and the final nod needs to come from the CDC based on real-world information.


The Department of Health and Human Sciences, which convened the meeting, issued a statement saying, “At this time, fully vaccinated Americans do not need a booster shot.”

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What are the larger objections to administering a third dose at this moment?


Even as debates are intensifying over the necessity of a booster shot — some countries in the Middle East have already started administering a third dose and the NHS has given green light to a Covid booster dose for 30 million of its vulnerable population — there is significant pushback from certain quarters.

Most of the objections to a booster dose have focused on issues of vaccine equity, lack of enough doses in some countries and the need to get most people inoculated first.


WHO Chief Scientist Dr Soumya Swaminathan has recently pointed out that with more high-income countries considering administering booster shots, they will require hundreds of millions of additional shots, potentially depriving access to vaccines in other nations. Taking to Twitter, she recently wrote, “Before boosters in some countries, we need to vaccinate the vulnerable in ALL countries. No evidence that boosters will be needed so soon after primary course. @WHO #COVAX goal to cover 40% population in ALL countries.”

Many scientists and experts have also pointed out that manufacturers of vaccines which are being administered now only have an Emergency Use Authorisation (EUA) for their product and the US FDA, instead of giving its nod to booster shots, should focus on granting full approval first. A full FDA approval would allow manufacturers to market and directly distribute their vaccines.

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Union Home Minister Amit Shah during a meeting with delegations of civil society organisations, in Kangpokpi, Wednesday, May 31, 2023.

There are also growing concerns in some quarters that all the data on reduced vaccine efficiency, breakthrough infections and the requirement of a booster shot can inadvertently promote greater vaccine hesitancy among the population which is yet to be vaccinated.

First published on: 13-07-2021 at 19:04 IST
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