TNM spoke to Dr V Ramasubramanian, Senior Consultant, Department of Infectious Diseases at Apollo Hospitals in Chennai on what it means to catch the infection and then recover from the disease.

Better immunity does not mean you wont get COVID-19 Infectious diseases expert
Coronavirus Coronavirus Sunday, April 12, 2020 - 17:13

Every day, more number of COVID-19 cases are being reported across the country. From a 10-month-old baby to persons over 90 years of age, the novel coronavirus has not spared any. Recovery rates, on the other hand, have been slow but positive. While discussing how to stay safe, the topic of one’s immunity levels features in bold. What does one’s immunity level have to do with Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) and what are some of the misconceptions we have?

TNM spoke to Dr V Ramasubramanian, Senior Consultant, Department of Infectious Diseases at Apollo Hospitals in Chennai on who is more susceptible to catching the infection, the possibility of getting infected again, on asymptomatic cases, herd immunity and the possibility of a vaccine in the coming days.

We know that people who are over 60 years of age, those with medical conditions and those with poor immunity levels are susceptible to novel coronavirus. But we have seen healthy youngsters and sometimes even children get infected. We have also seen very old people recovering from this disease. Why are some people more susceptible to catching the infection while others aren’t?

Everyone is susceptible to this infection. This is a novel coronavirus that did not come under the spotlight just until three months ago. No one is immune to it. Susceptibility-wise, no matter the age all of us are prone to it. The question that needs to be asked is —  who is at a higher risk of developing a complication? That is mainly the elderly and lesser so in the children.

In the case of the elderly, does it become a complication because the virus infection becomes severe? Or is it that the body’s response (the pro-inflammatory response) to the infection is so aggressive that it results in a complication?

Is that the reason why children who have a very simple immune system, that is not yet developed, are spared? Or is that the reason why the elderly (their bodies) who have developed a lot of antigens and built up a lot of immunity over the years, put up a stronger fight when infected resulting in a complication? We still don’t know but that is one of the theories.

What about pregnant women are they susceptible to the infection?

We are comparing a lot with the flu here. Flu is also a respiratory virus that also causes pneumonia. It also spreads in a similar fashion and you can’t differentiate between certain flu and COVID-19. For all these reasons, we compare it with the flu. Flu is common in very young children, pregnant women, elderly and people with underlying comorbidities. COVID-19 too is similar to flu with regard to age and the comorbidities factor but not the same in children and pregnant women. Flu causes severe infection in pregnant women but somehow COVID spares them the severity. We don’t know why yet.

Does better immunity mean you won't catch the infection?

No. If people with better immunity won’t get affected… then children within three years of age who are generally poor when it comes to immunity levels when they develop COVID-19, should all die. But that’s not the case. There is a lot for us to study the virus. We still don't know what are the protective antibodies against the virus.

What does it mean to “recover” from COVID-19?

98% who get infected with SAR-CoV2 recover. 80% recover without even going to the hospital and another 15% may go to the hospital, may end up in the ICU and still recover. Only 1% or less than 1% die. So when you say recover, it means you do have immunity to the infection.

For instance, if I have a viral infection like smallpox or chickenpox, it generally means that unless my immune system is compromised at a later stage, my body will be able to protect me from the same infection. In COVID, there have been cases where people have had a recurrence of the infection. Why does it happen? We don't know that yet.

World over, it is still not clear if a patient who recovers from COVID-19 has developed an immunity towards the virus or not. We have heard of a few stray cases being reported of someone who has recovered testing positive once again. What do we know about reinfection so far?

People who recover and clear the infection are out of danger. Only a small percentage might have a recurrence, but we are still not sure why this happens. In South Korea, 5-10% have shown symptoms of recurrence.

What about those who have recovered? What is the quality of life for them like after recovery? Do they suffer permanent lung damages?

We have had a virus like this only for three months. It looks like a flu infection, so once they recover, they should be able to go back to being normal completely. But for those who had bad pneumonia, can they have bad residual damage in the lung making it difficult for them to lead a normal life? It is possible but we have to wait and see.

Can you explain what herd immunity is? Is it a possible solution?

Herd immunity refers to the immunity of the population at large. For example, this virus, if a person gets infected, they can infect two to three people at a time and the chain progresses. It hinges on the fact that all the people that the infected person is exposed to have not been infected so far, are alive and may be susceptible to this infection. 

Beyond a certain level, if 80% have already been infected and recovered and if only 20% of the population is susceptible, then the chances of infecting three other persons may not happen. In other words, if the majority of the population have immunity, the chances of this virus spreading is very little. The pandemic will end.

This can be acquired in two ways — either 70 to 80% of the population must get infected and recover, and second is if they are vaccinated. As of now, vaccination looks quite far.

But even if the mortality rate is only 0.4%, which many experts believe to be a correct number, the 1.3 billion population (India) runs into several million. Can you take the chances of letting 50 million people die so the whole nation gets herd immunity and then survives? it is not a logical answer.

How do we know if someone has good immunity levels? What are some of the misconceptions when it comes to “boosting one’s immunity?”

It is nice for people to hear — you should take vitamin C, gargle with saltwater, etc. But there is no scientific rationale to it.

How long before we develop the vaccine?

At least 1 to 1.5 years is my reasonable guesstimate.

There are so many different treatment suggestions and drugs being used for COVID-19 treatment. What is the standard protocol? What treatment is generally given maybe?

There is no scientific recommendation for treatment of this condition as of now. Any recommendation is based on anecdotal references and comes with a list of “may help” possibilities. We adhere to what they use in China, the US, Italy… hydroxychloroquine is used, but is that beneficial? There are studies in the lab, done on 25 people, that show that it decreases the number of viruses in a person’s nose but does reduce the number of viruses alone help in recovery? We don’t know

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