How safe is the Covid-19 vaccine?

The vaccine for Covid-19 is here and the roll-out in India is imminent. In such a scenario, a looming question playing in the minds of everyone is whether the vaccine is safe. Do we go in for it once it becomes available? These are questions many would have to deal with sooner than later. Every step of research, every hiccup, and every milestone has been discussed and debated from newsrooms to drawing rooms, and on social media.

The vaccine candidates of Pfizer BioNTech, Bharat Biotech (Covaxin), and Serum Institute (Covishield, as the AstraZeneca-Oxford candidate is known in India) have applied for emergency use authorisation in India and vaccination is expected to begin soon. As per the latest status update from the government, beginning next week, for two days, India will carry out a dummy vaccination drive, in preparation for the eventual roll-out, which is touted as being the most ambitious mass immunisation programme in the country’s history.

In such a scenario, there are many who are concerned about adverse reactions to these drugs. Especially, given the fact that the process of making a vaccine, from the laboratory to the market, was done at breakneck speed, a feat that has never been accomplished before.

Experts say that at every step of clinical trials, safety comes before efficacy. Clinical studies conducted by pharmaceutical companies, despite moving at supersonic speed, have followed clear and concise guidelines given by both the World Health Organization (WHO), and the respective regulator of the country where the trials are being held.

Data is collected and shared. “If there are unusual side effects, the trials may be halted,” says Bharesh Dedhia, head, critical care, Hinduja Hospital. An apt example for this would be concerns over both the Pfizer and Moderna vaccine trials. During the U.S. Food and Drug Administration (FDA) review of both these vaccine candidates, the respective companies had included reports suggesting that several participants in the trial had developed facial paralysis, or what is called Bell’s palsy, as a side effect. But after statistical analysis was done, it was found that it occurred at the same rate as in the general public, and so was not attributed specifically to the vaccines.

This is why as the vaccine is deployed, post-marketing surveillance becomes critical and will be monitored both by companies and regulators.

Mechanism of the roll-out

To understand if India is prepared to deal with the fallout of any adverse reaction to the vaccine, let us first examine the structure of the mechanism to roll it out. The Government of India set up the National Expert Group on Vaccine Administration for Covid-19 (NEGVAC)—headed by Dr. Vinod Paul, the member (health) of government think tank NITI Aayog—to prepare a plan for the roll-out of the vaccine. At the state level there is a steering committee, a task force, and a control room. Once the vaccine is made available, efforts would focus on delivery, transportation, and distribution.

The state health departments will also monitor meetings of any adverse event following immunisation (AEFI). The WHO defines AEFI as any untoward medical occurrence which follows immunisation.

Government guidelines say that there will be an outreach site and the vaccinator officer (a trained medical officer or doctor in-charge of the health facility) will ensure management of minor AEFI like fever, pain, or swelling at the site of the injection.

These are minor side effects, and are common in many other vaccinations, and should subside within a day or two. If they persist beyond two days, a doctor must be consulted. For serious side effects leading to anaphylaxis (allergic reaction), a patient will need to be hospitalised and the vaccinator must arrange for transfer of the patient to the nearest primary health clinic or district hospital. State governments have been directed to set up an AEFI centre at every block in either the district hospital or at a medical college.

All details of the patients will be maintained for record and follow up.

“The human immune system and system biology are very complex and vary from person to person,” says Amit Kumar Dinda, professor at the department of pathology, All India Institute of Medical Sciences (AIIMS). According to him, minor side effects are part of vaccination. And with many vaccines in the market, different people can be covered by different vaccines. For example, one could be allergic to an ingredient of a vaccine.

In fact, the WHO argues that the search for a ‘perfect’ vaccine—which provides a blanket protection for everyone who receives it and is entirely safe for everyone—is a chimera. No vaccine is perfect. And since all vaccines in development are not expected to work on every person, it is necessary to pick the one which suits one the best.