Second booster shields elderly from COVID but protection wanes quickly: Study

Protection against severe illness did not wane during the six weeks after the dose but more follow-up study was needed to evaluate its longer-term protection, the researchers said.

Reuters

April 06, 2022 / 09:30 IST

Representative image.

A fourth dose of the Pfizer/BioNTech vaccine lowered rates of COVID-19 among the elderly but the protection against infection appeared short-lived, a large study in Israel has found.

The second booster's protection against infection dwindled after four weeks, Israeli researchers showed in their study published on Tuesday in the New England Journal of Medicine.

Protection against severe illness did not wane during the six weeks after the dose but more follow-up study was needed to evaluate its longer-term protection, the researchers said.

The study on 1.3 million people aged 60 and older looked at data from the Israeli Ministry of Health database between Jan. 10 and March 2, when the Omicron variant was predominant.

It comes ahead of a meeting by the U.S. Food and Drug Administration on Wednesday to discuss the need for additional boosters, a week after the United States authorised a second booster shot for people aged 50 and older amid a spread of the Omicron sub-variant BA.2.

COVID-19 Vaccine

Frequently Asked Questions

How does a vaccine work?

A vaccine works by mimicking a natural infection. A vaccine not only induces immune response to protect people from any future COVID-19 infection, but also helps quickly build herd immunity to put an end to the pandemic. Herd immunity occurs when a sufficient percentage of a population becomes immune to a disease, making the spread of disease from person to person unlikely. The good news is that SARS-CoV-2 virus has been fairly stable, which increases the viability of a vaccine.

How many types of vaccines are there?

There are broadly four types of vaccine — one, a vaccine based on the whole virus (this could be either inactivated, or an attenuated [weakened] virus vaccine); two, a non-replicating viral vector vaccine that uses a benign virus as vector that carries the antigen of SARS-CoV; three, nucleic-acid vaccines that have genetic material like DNA and RNA of antigens like spike protein given to a person, helping human cells decode genetic material and produce the vaccine; and four, protein subunit vaccine wherein the recombinant proteins of SARS-COV-2 along with an adjuvant (booster) is given as a vaccine.

What does it take to develop a vaccine of this kind?

Vaccine development is a long, complex process. Unlike drugs that are given to people with a diseased, vaccines are given to healthy people and also vulnerable sections such as children, pregnant women and the elderly. So rigorous tests are compulsory. History says that the fastest time it took to develop a vaccine is five years, but it usually takes double or sometimes triple that time.

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