New Delhi, April 7
India recorded 1,15,736 new Covid-19 cases in the last 24 hours, the biggest-ever single-day spike since the onset of the pandemic, taking the overall tally to 12,801,785 on Wednesday. The steep incline in cases is very concerning, as the new Covid variants have infiltrated the population, and some of these variants are known to be more infectious and lethal, said Manisha Juthani, Associate Professor of Medicine and Epidemiology at Yale School of Medicine and Yale Medicine infectious diseases specialist.

She added that long-lasting symptoms after Covid will be a worldwide problem and nearly 30 per cent people are likely to suffer from long Covid.

Excerpts from the interview

Q: India is amid the second wave of coronavirus. The rise in cases is too steep, sharper than the first wave. Is it consistent with the pattern seen in other virus pandemics?

A: This steep incline in cases in India is very concerning for new Covid variants infiltrating the population. Some of these variants are known to be more infectious and lethal. The highest concentration of cases is in Maharashtra with Mumbai being a travel hub. This suggests that travellers have brought in variants which are rapidly spreading in the population.

Q: Usually, experts say human behaviour is considered a major factor linked with a spike in coronavirus cases. But some experts also point at a probability of a new strain, possibly behind the second wave, which maybe infectious, not fatal, leading to a surge in cases in many places in India?

A: New variants from around the world have been identified in India. There is the concern of the 'double mutant' in India that has also now been identified in San Francisco. Anecdotally, I know of several people in India that have tested negative for Covid, but who have all the clinical features suggestive of Covid. Sometimes, one member of the family tests positive but the others test negative, all with the same symptoms. It is possible that a variant is spreading with a mutation that results in false negative tests. This is particularly concerning because other family members can get exposed if they believe the index patient does not have Covid. When the first wave was receding in India, it seemed that variants may not have yet reached. With the current explosion in cases, variants seem to at least be playing a part.

Q: Long Covid is emerging as a major problem in the UK. Do you think, globally it could be a major issue too?

A: Long Covid will be a worldwide problem. Up to 30 per cent of infected individuals worldwide may end up suffering from long term symptoms. Some promising news is that vaccination seems to ease these symptoms in some people.

Q: Experts say that seasonal change has no effect on coronavirus. There were some locations, for example Delhi (at the onset of winter season), which saw a high number of coronavirus infections early on, followed by a decline (December-January), is facing a "second wave" of increased cases, at the beginning of summer season in March.

A: We have been learning about Covid for over a year now. The anticipated seasonal variation that occurs with other respiratory viruses has not consistently proven to be the case. The common thread for spread appears to be close contact, particularly in indoor settings. In the winter season, indoor gatherings seem to be a source of spread because people remain indoors for warmth. In hot locations in the summer, indoor gatherings also seem to be sources of spread, likely because it is too hot to remain outdoors, and people gather indoors. Heating and air conditioning might even contribute to the spread of viral particles.

Q: Is there a possibility that a second wave may not lead to increase in fatality or increase in Covid patient's admission to Intensive Care Unit (ICU), however the viral infection may have a long-lasting health impact in patients, for example, kidney, live or lungs damage?

A: Given that hospitals already appear to be filling up in many parts of India, it seems likely that hospitals will continue to feel the burden of caring for Covid patients. In addition, we know that appropriately 30 per cent of Covid patients can go on to have chronic symptoms such as shortness of breath or fatigue. End organ damage can happen with Covid as well, particularly after long hospitalizations. I anticipate that India will have a surge in hospitalized patients in addition to those that suffer long term consequences of Covid.

Q: Experts say young people may be behind the increase in cases. Is it possible that young people, who have contracted the new strains of coronavirus, are spreading it to more than one person, leading to a spike in cases?

A: Vaccinations have begun in India, but many young people are not vaccinated yet. Adults in their 20s and 30s remain the most social thereby transmitting the virus from one another. This age group may also be travelling more. The US is seeing a surge of cases among young adults primarily because of congregating behaviours and because the youngest adults have not been eligible for the vaccine until now. In India, older adults are still getting infected, either because they haven't received the vaccine yet, only received one dose, or are exposed to other people. It is unclear if the current spike is because of young people, but young adults have always been the most likely to engage in social behaviours and get infected.

Q: The US and Europe have already faced the second wave of coronavirus, is there any learning for India from the western countries?

A: Throughout the world, when public health measures (masking and physical distancing) have been put in place, cases have been controlled. Lockdowns have been necessary and effective in various regions of the world. With a very steep rise in cases, in order to maintain hospital capacity, more restrictions will be necessary.

(Sumit Saxena can be contacted at sumit.s@ians.in )

Yale Prof: New Covid variants infiltrating Indian population, more lethal & infectious