Do Covid Survivors need only 1 Shot of a 2-Dose Vaccine??

by Shoubhik Sen

The Vaccination Drive in India will open up for all people above 18 years of age from May 1. Worldwide too, authorities are opening up Covid vaccinations for more and more people. However, this may not be a wise decision, given the strained global supply.

Thus in such a situation, a wiser decision would be to limit the doses for Covid Survivors to 1 instead of 2. Apart from vaccine shortage, another reason this is being considered, is because the efficacy of such a step has been proven in multiple studies. Let’s have a look at whether this will be a good decision or not.

The Covid Survivor Study in L.A

The conversation around this began around December last year. More than 1,000 staffers at Cedars-Sinai Medical Centre (Los Angeles, CA) volunteered for a study. The goal was to pinpoint how immune reactions to the virus might vary among infected and non-infected.

Research leader Susan Cheng revealed the results of the test recently, which gave out an interesting data. Those who had recovered from Covid-19 responded to their 1st dose/shot very effectively. In fact, their immune response rivalled their colleagues who never got infected and took 2 shots/doses.

LA Covid Immunity Vaccine Test

Thus, many scientists around the world are deliberating on this. Whether 1 dose of vaccine works on Covid survivors the same way 2 doses work on the non-infected.

We did not expect that this was going to jump out like a smoking gun

Susan Cheng (Research Leader, CSMC & Co-author, Nature Medicine Write-up on the same)

Other Findings pointing towards it

A number of studies came out afterwards, seconding the previous research. An Italian research published in the New England Journal of Medicine also corroborated this. It said that if you already have the virus, your immune response after 1 vaccine is likely to be even better than a never-infected person’s after 2.

Covid Immunity

This finds further elaboration in a recent study co-authored by Sajadi. This one fit into a recent flurry of findings, all pointing to the same direction. This study also reiterates the above points. It says that the immune system of a person who’s already had Covid, “remembers” the virus. So the 1st shot/dose of vaccine acts as a powerful booster for existing defences.

The data is very clear. Every Study has shown you get a very clear and strong memory response

Mohammad M. Sajadi (Associate Professor, School of Medicine, University of Maryland)

Furthermore, he highlights the implications of this step at time of strained global supply. According to his calculations, giving previously infected persons just 1 shot/dose of mRNA vaccine could free up >110 million doses.

Position of the World on this Covid Update

A study in “Science” found that in Covid survivors, vaccinations massively boosted immunity against variants. Thus, many nations jumped on the bandwagon to test this out.

Since February 2021, several European nations like France, Italy, Spain, Germany etc, have adopted this policy of administering just 1 out of 2 doses to the survivors. Israel in fact, went 1 step further and withheld vaccines from recovered patients. However, they too shifted to the 1 dose policy this February.

Covid and the World

Israel is the world leader in coronavirus vaccinations. New research from their claims that if administered as a booster to Covid survivors, it will grant added protection from the newer variants coming from Brazil, U.K and South Africa.

We think that our study supports the recommendation to administer one vaccine dose to recovered individuals to protect against the original and SARS-CoV-2 variants of concern

 Michal Mandelboim (Head, National Center for Influenza and Respiratory Viruses)

In the U.S., the Centres for Disease Control and Prevention still recommends two vaccine doses for people who have had Covid. However, the mounting evidence that one vaccine could be enough is under discussion. The U.S. has administered enough doses for 31% of its population, while Israel has given enough for 57%, according to the Bloomberg Vaccine Tracker.

Skepticism Regarding this Step

At the end of the day, this medical intervention is still an ongoing experiment. Any serious consideration of this option will require more data. Some skeptics also point out that it is easier to give everyone two doses than to figure out who needs only one.

Mohammad Sajadi himself said that though effective in the tests conducted, it won’t be viable to administer someone a medical procedure that they don’t need necessarily. If a patient who’d had Covid asked Sajadi at this point whether they needed a second vaccine, he said, he’d say it would make sense to skip it if nothing in their medical history indicated issues with immune responses.

On the other hand, Cheng at Cedars-Sinai said she would still default to the CDC guidance calling for two vaccines, even for people who’ve had Covid. The data does suggest, however, that one dose could be enough, she said — and that could be true for other types of people as well

Finally, the status of whether we can accept this hypothesis as genuine or not is unclear. This quote aptly defines the situation at hand

We’re just at the tip of the iceberg of figuring out 

Susan Cheng

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