Waving testing requirement for the fully vaccinated is an ill-considered decision: Giridhara Babu

Since fully vaccinated people too can get infected and transmit the virus to others, waving off RT-PCR testing, as done by the Maharashtra government, can lead to unnecessary spread of the virus. The decision has not been taken from a public health perspective but more to reduce inconvenience to passengers travelling by air, says Dr. Giridhara Babu.

On July 14, Maharashtra government announced that people who have received both doses of a Covid-19 vaccine can travel to the State by air without a negative RT-PCR report. However, they should carry certificates stating they are fully vaccinated. Earlier rules mandated that a test had to be taken 48 hours prior to the travel and only those with a negative RT-PCR test could enter Maharashtra.

In an email, Dr. Giridhara Babu, Epidemiologist at the Public Health Foundation of India, Bengaluru explains why doing away with RT-PCR testing is not correct and how it could endanger others.

Since fully vaccinated people can still get infected, is it a correct decision by the Maharashtra government to do away with the requirement of RT-PCR testing by fully vaccinated people?

We need to understand that testing is done to identify people with infections so that they can be isolated. This applies to everyone irrespective of the vaccination status. Increasingly, it is seen that the vaccinated persons can get infected. Not testing the vaccinated persons is an ill-considered and unjust decision, mostly to reduce the inconveniences to the vaccinated persons.

From the perspective of rights of the unvaccinated, it is important to protect them from getting the infection from everyone, including vaccinated persons. There is also evidence that there is high incidence of breakthrough infections in the vaccinated persons, even among those who have taken two doses of mRNA vaccines.

The efficacy of the vaccines is tested against hospitalisation and in preventing deaths. While reductions in infections is the ultimate goal of higher vaccination coverage, this is not the primary outcome in vaccine trials or possible in settings with low vaccination coverage. I would recommend testing everyone, especially the vaccinated persons.

WHO says vaccine breakthrough infections will be only mild or asymptotic. So how likely are fully vaccinated people spreading the virus to others when infected?

There is strong evidence that vaccination offers the greatest protection against death and hospitalisation. However, there is little evidence that the ability to transmit COVID-19 will greatly diminish. The transmission, even when is at a lower rate, can [happen] from the vaccinated to unvaccinated individuals. Vaccinated people could potentially still become infected and spread the virus to others.

Is the mild/asymptotic infection in the fully vaccinated people mean that the viral load is less and hence less likely to infect others?

Although COVID-19 vaccines might reduce viral load in persons with breakthrough infection, there is limited evidence whether it will result in lower viral shedding, thereby further suppress the onward transmission. Evidence available for mRNA vaccine suggests that the infections occurring after 12 days of vaccination have significantly reduced viral loads at the time of testing.

We need to establish the relation of viral load and viral shedding for different vaccines and against different variants of concern. In the absence of such evidence, it is premature to conclude that vaccinated persons will have lower viral shedding and, therefore, are less contagious.

Since only 8% in India are fully vaccinated, is exemption from RT-PCR testing for the fully vaccinated a correct decision?

In India, it is early to consider exempting from testing. I do see a great opportunity for novel rapid tests, especially if there are alternative non-invasive options. Exemption from RT-PCR testing may be replaced once such tests are available, reliable, and feasible to implement in India. Also, in the symptomatic persons, our earlier study has shown high sensitivity while using the rapid antigen test. In persons with no symptoms, RT-PCR is the best available option as of now.

At a time when vaccine shortage has been reported from several States and vaccination coverage is not uniform in urban and rural areas and even within urban areas, will treating the fully vaccinated people differently result in more inequities?

Absolutely, given the global dynamics of vaccine injustice, unfortunately, getting vaccinated is a rare privilege due to many reasons. Some of these include non-eligibility, non-availability and unaffordability. Treating the vaccinated people differently will induce and worsen the inequities in the community, including those exacerbated by inequitable health system access. It is also unethical because if exempted, the vaccinated can get infected and infect those who have had no access or opportunity to get vaccinated yet.

At what stage of vaccination coverage can the fully vaccinated people be treated differently, if at all?

Given a choice, I would rephrase the question differently. The absolute priority is to protect the unvaccinated. Therefore, if anyone deserves treating differently, it is the unvaccinated. Every effort should be made to ensure that those who do not have access to health system are brought within the ambit of vaccination through strong micro-planning and better mobilization strategies.  It is important to plan outreach sessions and ensure that every person gets an opportunity. This is really hard work that we do in all other vaccination campaigns. This is how we should treat differently, and the disempowered and vulnerable communities are favoured, not the other way round.

Even after reaching a sufficient level of vaccine coverage, the risk of a new outbreak persists because the surrounding communities or nations might not have attained the required level for their population. More than the privilege, fully vaccinated individuals have dual responsibilities. First, they need to maintain preventive measures to prevent unvaccinated people from getting the infection, who otherwise are at risk of severe disease or death. Second, they need to ensure how they can help others to get vaccinated.

Published in The Hindu on July 18, 2021