Ahead in curbing Covid-19 pandemic, India must monitor now: Experts

One of the few to contain Omicron well, it has seen stronger peaks followed by declines

Microsoft Co-founder Bill Gates has recently said in an interview that the chance of a more virulent variant emerging is “way above 5 per cent”, and that we have not seen the worst of the pandemic yet.

Experts across the globe agree that words of caution and active, coordinated monitoring and surveillance are a must to predict and mitigate risks of waves and the spread of infections across regions.

In this context, India, which is home to 1.4 billion people, appears to be faring well. It is one of the few countries that have contained the Omicron-led wave (third one in India) reasonably well. After cases started to subside around September 2021, India maintained a relatively stable rate of infection for almost ten weeks before it was hit by Omicron, a significant mutation in Sars-CoV-2 distinct from the Delta variant that led the second wave in this country.

Unlike Western countries and some of the Asian economies, the virus has followed a very specific pattern in India. The peaks are more pronounced which are followed by cases starting to fall until they hit a peak again. For instance, after the first wave, which ended in September 2020, cases declined for 146 days. Thereafter cases started rising again in February 2021, hitting a peak in May 2021. The next time they declined for 106 days. In August, cases increased for a brief period of 10 days before declining again. The next rise in cases came after 112 days in December 2021 during the Omicron wave. But after they hit the peak in January-end, they declined to their lowest point in April — a period of 80 days.

This is because by January almost 90 per cent of India had received at least one vaccine dose, and a wide section of the population had been infected.

In contrast, the United States has witnessed six declines in the last two years, with shorter term periods. After the first wave, cases declined for 54 days in the US, before rising again. The longest period of decline there was between January and April this year, when cases declined for 80 straight days. There were periods in the US when cases remained within a certain bandwidth. France also followed a similar strategy and so did South Korea.

South Korea seems to have controlled the infection very well since 2020, and that leaves behind a relatively naïve population. As the variants of Sars-CoV-2 become more transmissive, South Korea has witnessed daily fresh go up steeply from around the 5,000-mark in January to four lakh in mid-March. In the last two weeks, cases have shown signs of coming down.

Experts like Gagandeep Kang, microbiologist and professor at Christian Medical College (CMC) Vellore, say that India indeed is in a good position now. “We are in a good place, well-vaccinated and widely infected. Currently, cases are low and there are very few hospitalisations,” she says.

“India has had long periods of endemic infection unlike other countries,” points out T Jacob John, senior virologist and former head of the departments of clinical virology and microbiology at CMC Vellore. John says that any period of stable rate of infection for four continuous weeks or more can be termed the endemic phase of the pandemic.

India, however, needs to work on its future plan. “Detection of new variants capable of causing severe disease in the vaccinated and infected is an area where India needs to work now. Moreover, duration of protection against severe disease with different variants with each type of vaccine will determine number, timing and type of booster,” Kang added.

Dileep Mavlankar, director, Indian Institute of Public Health, and former professor of IIM Ahmedabad, feels that now is the time for sero-surveillance. “Apart from checking antibody levels, we also need to do a survey on T-cell immunity. Even if antibodies are low but one has memory cell immunity, they will fight future infections. These can determine the booster dose policy,” he adds.

Mavlankar also feels that influenza-like illnesses (ILIs) and severe acute respiratory diseases need to be monitored and tested actively. “If we are missing testing for ILIs, the daily case count may seem low,” he says, adding that another important marker is the district-wise spread of infection. “We need to see if infection is concentrated in some parts, or is spreading rapidly across the country,” Mavlankar says.