Vaccines prevent severe COVID, even from Delta variant: Study

The research published on Monday -- focusing on prevention of severe Covid and death, not infection -- looked at 22 million people over 50 and found those who had received jabs were 90 percent less likely to be hospitalised or die.

October 11, 2021 / 11:17 IST

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Vaccination is highly effective at preventing severe cases of Covid-19, even against the Delta variant, a vast study in France has shown.

The research published on Monday -- focusing on prevention of severe Covid and death, not infection -- looked at 22 million people over 50 and found those who had received jabs were 90 percent less likely to be hospitalised or die.

The results confirm observations from the US, the UK and Israel, but researchers say it is the largest study of its kind so far.

Looking at data collected starting in December 2020, when France launched its jab campaign, the researchers compared the outcomes of 11 million vaccinated people with 11 million unvaccinated subjects.

They formed pairs matching an unvaccinated individual with a vaccinated counterpart from the same region and of the same age and sex, tracking them from the date of the vaccinated person's second jab to July 20.

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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