Coronavirus | Vaccine dilemma — to take or not to take Covaxin

A medic fills a syringe with COVAXIN before administering it to a health worker during its trials, at the Gujarat Medical Education and Research Society in Ahmedabad on November 26, 2020.

A medic fills a syringe with COVAXIN before administering it to a health worker during its trials, at the Gujarat Medical Education and Research Society in Ahmedabad on November 26, 2020.

As India’s largest vaccination drive using two COVID-19 vaccines is all set to begin on January 16, healthcare workers, who are the first to receive the vaccine, will have no option to choose one vaccine over the other . The same rule applies to other high-risk groups that would get the vaccine on priority.

Addressing a press conference on January 12, the Union Health Secretary Rajesh Bhushan said: “At many places in the world, more than one vaccine is being administered, but at present, in no country, vaccine recipients have the option of choosing the shots.”

True, in the U.S., vaccines from both Pfizer and Moderna are available and recipients, who are healthcare workers and nursing home residents, have no option to choose the vaccine. In the U.K. too people will either receive a Pfizer vaccine, Moderna or AstraZeneca’s but cannot choose one over the other. But the similarities of not providing the recipients the option to choose a vaccine, be it in the U.S., the U.K. or India end there.

What the Health Secretary did not mention is that the safety and efficacy data used by the regulators in India, the U.S., and the U.K. to grant an emergency use approval are very different. While people in India will have to take a particular vaccine without knowing its efficacy and interim safety, efficacy from phase-3 trials are known for Pfizer, Moderna and AstraZeneca vaccines that people in the developed countries get.

The difference

The emergency use approval granted by the U.S. FDA to Pfizer and Moderna and by the U.K. regulator to three vaccines — Pfizer, Moderna and AstraZeneca — have been based on interim safety and efficacy data from large phase-3 trials with median follow-up of at least two months after the second dose. While both Pfizer and Moderna have nearly identical efficacy of 95%, the efficacy of AstraZeneca vaccine is 62% even when standard dose for the first and second dose is considered, which is more than 50% required for approval.

In contrast, the Indian regulator issued restricted use approval for the Pune-based Serum Institute’s Covishield based on safety and immunogenicity tested in India on a small number of participants and safety and efficacy data from large trials of over 24,000 participants in Brazil, South Africa and the U.K. The bridging study did not require Serum Institute to test the efficacy of Covishield in India but rely on efficacy data from trials done outside India.

The restricted use approval was granted to the Hyderabad-based Bharat Biotech’s Covaxin even in the absence of any efficacy data. The approval was solely based on a small number of participants studied during phase-1 and phase-trials; vaccine efficacy is studied only during a phase-3 trial.

In addition, Covaxin has been greenlighted in a “clinical trial mode” as a matter of “abundant precaution”, with no clarity on whether medical care in case of adverse events and compensation would be provided, and informed consent has to be taken from the recipient before immunisation. There are no such conditions or riders in the case of Covishield. Hence, is it correct to compare the situation in India with other countries using vaccines with interim safety and efficacy levels known?

According to the Union government, vaccine sites will offer either Covishield or Covaxin in order to avoid providing recipients the option to choose one vaccine over the other. Since COVID-19 vaccination is not compulsory, people walking into a site that provides only Covaxin can choose not to get vaccinated.

But is it ethical to offer one healthcare worker the Covaxin whose efficacy is unknown and another healthcare worker the Covishield whose efficacy is known even though both face the same risk of infection at work? “This situation could have been avoided if the government had waited for few more weeks for the efficacy data of Covaxin to become available before granting it restricted use approval,” says the Bhopal-based Anant Bhan, a researcher in global health and bioethics. “They could have begun vaccinating with Serum’s Covishield and added Covaxin after approving it based on efficacy data.”

Will healthcare workers and others who have refused to get vaccinated with Covaxin be offered another chance to get the vaccine on priority when data becomes available showing the vaccine has at least more than 50% efficacy, as initially stipulated by the Indian regulator for approval? Likewise, if Covaxin is found to have less than 50% efficacy, will everyone who has been immunised with this vaccine be offered Covishield or another highly efficacious vaccine?

Informed consent

People at the vaccine sites offering Covaxin are required to take an informed consent from each recipient before immunisation. “Good consent also requires time. Some may want a day’s time to think over before consenting. Will this be allowed or will the person be compelled to give his/her consent then and there?” asks Dr. Bhan. Or will people be informed in advance which vaccine they would be getting in order to avoid delay in getting the informed consent? Even then, who will explain the details of the vaccine prior to taking an informed consent from healthcare workers and has the time taken for this process factored in? Apparently, the vaccine dry-run conducted across many States has not tested these.

State governments will decide which vaccine goes to which sites. But how can States ensure the allocation of healthcare workers to sites, particularly those that offer Covaxin, is done without bias? “There has to be fairness — either random allocation or something to that effect. It could also be those who are willing to take Covaxin under “clinical trial mode” are assigned to sites offering the vaccine,” says Dr. Bhan.

According to The Print , a few States have already said they would use Covishield as the “default option” and Covaxin as a “buffer stock”.

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Printable version | Jul 3, 2022 11:48:35 pm |