How Pfizer’s Covid-19 vaccine works

REUTERS/Thomas Peter/File Photo

REUTERS/Thomas Peter/File Photo

Published Nov 10, 2020


CAPE TOWN - On Monday, Pfizer announced positive early results from its late-stage vaccine trial.

According to the company the vaccine was more than 90 percent effective in preventing Covid-19 among volunteers who had no evidence of prior infection.

The type of vaccine developed by Pfizer and BioNtech is known as messenger RNA (mRNA) vaccine.


“If an mRNA vaccine is approved for coronavirus, it would be the first of its type. It's a very unique way of making a vaccine and, so far, no (such) vaccine has been licensed for infectious disease,” said Prof. Bekeredjian-Ding.

Unlike conventional vaccines, mRNAs do not use a weakened version of the virus to stimulate immunity, but use the virus’ genetic code instead.

Once the mRNA vaccine is injected, it enters cells and tells them to create antigens.

These antigens are recognised by the immune system and help it to prepare to fight off coronavirus.

Because mRNAs do not use the virus in their production, this means the vaccines can be produced much faster and cheaper than a conventional vaccine.

Some experts believe they are safer for patients, as they do not contain the virus.

Traditional vaccines are made up of small or inactivated doses of the whole disease-causing organism, or the proteins that it produces, which are introduced into the body to provoke the immune system into mounting a response.

mRNA vaccines, in contrast, trick the body into producing some of the viral proteins itself. They work by using mRNA, or messenger RNA, which is the molecule that essentially puts DNA instructions into action.

Meanwhile, Brazil’s health regulator Anvisa announced on Monday, that it has suspended clinical trials of China’s Sinovac coronavirus vaccine, long expected to be one of the first to be approved in the country, following a “severe adverse event.”

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