Is Pfizer COVID-19 vaccine effective against the Indian strain?

Mumbai, India, COVID-19 vaccine
People line up to receive vaccine for COVID-19 outside a vaccination centre in Mumbai, India, Saturday, May 29, 2020. Image Credit: AP

Paris: The Pfizer vaccine is slightly less effective but appears to still protect against the more transmissible Indian strain of the virus that causes COVID-19, according to a study by France’s Pasteur Institute.

“Despite slightly diminished efficacy, the Pfizer vaccine probably protects” against the Indian variant, according to laboratory test results, said Olivier Schwartz, the institute’s director and co-author of the study that was published on the BioRxiv website ahead of peer review.

The study sampled 28 healthcare workers in the city of Orleans. Sixteen of them had received two doses of the Pfizer vaccine, while 12 had received one dose of the AstraZeneca vaccine.

People who had received two doses of Pfizer saw a three-fold reduction in their antibodies against the Indian variant, B.1.617, according to the study, but were still protected.

“The situation was different with the AstraZeneca vaccine, which induced particularly low levels of antibodies neutralising” the Indian variant, the study said.

Patients who had had COVID-19 within the past year and people vaccinated with two doses of Pfizer retained enough antibodies to be protected against the Indian variant, but three to six times less antibodies than against the UK variant, Schwartz said.

The study shows that “this variant.. has acquired partial resistance to antibodies,” Schwartz said.

Since first emerging in late 2019 in China, the SARS-CoV-2 virus that causes COVID-19 has developed several variants, usually named for the places where it first appeared including the so-called South Africa and UK strains.

The variant first detected in India appears to be much more transmissible than earlier variations.

It has now been officially recorded in 53 territories, according to a World Health Organization report.

To try to curb its spread, France and Germany have re-introduced tighter rules on arrivals from affected countries, including the United Kingdom.

What’s in the Pfizer-BioNTech vaccine?

The active ingredient is messenger Ribonucleic Acid (mRNA) which triggers the production of the protein found on the spikes of the new coronavirus (SARS-CoV-2).

The vaccine was designed on computers and synthesised in laboratories. So it’s synthetic, not natural since it’s not extracted from actual viruses or grown in a cell, like classic vaccines. This means it can be manufactured in large numbers very quickly, and can also be tweaked fast enough to keep pace with the virus’ mutations.

Image Credit: Graphic News

How does the vaccine work?

The vaccine enables the production of the “spike proteins” that sit on the coronavirus’ crown and is used to gain entry to cells. The mRNA in the vaccine provokes the production of spike protein in the cells of the human body, and the body responds by producing antibodies, and B cells and T cells are activated, according to Ugur Sahin, the chief executive of BioNTech that co-developed the vaccine with Pfizer.

Why the vaccine requires cold storage?

All mRNA vaccines are highly fragile and should be kept at extremely low temperatures. Or else, it will disintegrate.

For long-term storage, the Pfizer-BioNTech vaccine has to be stored at -100F (-70C), and that requires specialist cooling equipment. Pfizer’s innovative distribution container keeps the vaccine at that temperature for 10 days if it’s unopened, according to a New Scientist report. The containers can be stored for up to 30 days if they are replenished with dry ice every five days. After thawing, the vaccine can be stored in a regular fridge for up to five days.

How fast can the vaccine be produced?

The full Pfizer-BioNTech vaccine dose is 30 micrograms (a microgram is a millionth of a gram). It will technically require only several months to produce two doses for the 7.8 billion people in the world. But it’s not that simple.

Pfizer’s chief executive, Albert Bourla, said that it could have 30 to 40 million doses of the vaccine before the end of the year, which would be enough for 15 to 20 million people. Pfizer and BioNTech say they could ramp up to 1.3 billion doses a year. Read more