HomeNewscoronavirusPfizer, Moderna COVID-19 vaccines work in real-world conditions, found up to 90% effective: CDC

Pfizer, Moderna COVID-19 vaccines work in real-world conditions, found up to 90% effective: CDC

The result of the CDC study largely validates the findings of the clinical trials, in which Pfizer and Moderna vaccines were found to be nearly 95 percent effective.

March 29, 2021 / 21:33 IST
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A medical health worker checks on a person who received a vaccine shot |File image (Photo: Joao Silva/NYT)
A medical health worker checks on a person who received a vaccine shot |File image (Photo: Joao Silva/NYT)

The COVID-19 vaccines of Moderna Inc and Pfizer-BioNtech were found effective in real-world conditions, the Centres for Disease Control and Prevention (CDC) - the United States' national public health agency- said in a report released on March 29.

Both the vaccines were found to be 90 percent effective if two doses of the vaccine were given to the beneficiaries, it said.

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In the case of a single dose, the efficacy in real-world conditions was found to be 80 percent, as per the findings of the CDC's 'Morbidity and Mortality Weekly Report'.

On full vaccination - when both the doses have been administered to the beneficiaries - the vaccine was found to be 90 percent effective in even preventing infections that show no symptom, the study claimed.

COVID-19 Vaccine
Frequently Asked Questions

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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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