Dr. Purvish Parikh provides his expert take on COVID-19 reinfection considering the latest data available, and addresses the question of it being detrimental to an individual.

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Hospital beds' availability has once again become scarce in Mumbai and Delhi. This is likely to be a reflection of the so-called "second wave" of COVID-19 infections.

Therefore there are important questions in every doctors' minds:

1. Do patients infected with COVID-19 remain immune from further infections?
2. Is doing blood antibody testing important to decide whether that patient is protected or not?
3. What happens to patients who got infected, recovered but blood test does not show any protective antibodies?
4. Is there a role of T cell immunity that we have not evaluated so far?

Earlier cases reported as having reinfection with COVID-19 were met with criticism for incomplete documentation and led to vehement arguments on both sides. The recent case from Hong Kong has put to rest all doubts. The 33 year old patient under consideration was first hospitalised for COVID-19 on March 26th and discharged on 14th April. Two tests documented his converting to negative status. He recovered and was having normal activity including international travel. Almost five months later he tested positive once more. He continued to remain asymptomatic, the only reason to test him was the mandatory reentry screening on returning after an international flight from Spain.

This becomes a very important question among the minds of doctors in India. Our country now has 87,000+ healthcare professionals infected by COVID-19, of which at least 573 have died (data of six states).

I suggest we take a step back and get the bigger picture. Do we know of other examples of infections that persist even after years? The answer is yes!

1. CytomegaloVirus (CMV) infection usually occurs within the first month of life - while still admitted in the hospital nursery. The virus remains dormant in our bodies for life. And any time the immunity is compromised, it has the potential to lead to severe morbidity and even death.
2. Varicella zoster infects many of us for various reasons. This can also persist in our body and result in shingles at any time the body's immunity is compromised - take the example of in patient with uncontrolled diabetes. It can even lead to post-herpetic neuralgia that compromises quality of life significantly.
3. Human Immunodeficiency Virus (HIV) has been persisting since decades. We have got effective treatment for the same but are still struggling to have it translated to the majority of patients. Indian health authorities have the goal of 90-90-90 viz 90% of HIV patients should know their status, 90% should be on proper antiviral therapy and 90% should become virally suppressed.
4. Tuberculosis (though not a virus) is also a relevant example. Infection remains alive and kicking, even though patients can be diagnosed relatively easily and most require treatment lasting only six months. Also, reactivation can occur at any time, can result in multidrug resistance and finally lead to death.

In all the above examples, persistence of the infective agent occurs for years to lifelong. They can also flare up leading to life-threatening situations. Has this been seen with COVID-19? The answer is a clear no.

Despite reinfection, there is not a single documented case of the virus leading to a clinically detrimental effect. Reinfection seems to be of no consequence for the concerned person. So, according to my interpretation (with the limited data available today), doctors who have got infected with COVID-19 once should continue to be safe irrespective of whether their bodies produce IgG antibodies to COVID-19.

Whether it will have a role in propagating the pandemic is an entirely different question that we can discuss in a future article.

Disclaimer- The views and opinions expressed in this article are those of the author's and do not necessarily reflect the official policy or position of M3 India.

The author, Dr. Purvish Parikh is the Group Oncology Director & Professor of Medical Oncology at Shalby Cancer & Research Institute, Ahmedabad.