The pandemic is sweeping through India at a pace that has staggered scientists. Daily case numbers have exploded since early March: the government reported 273,810 new infections nationally on 18 April. High numbers in India have also helped drive global cases to a daily high of 854,855 in the past week, almost breaking a record set in January.

Just months earlier, antibody data had suggested that many people in cities such as Delhi and Chennai had already been infected, leading some researchers to conclude that the worst of the pandemic was over in the country.

Researchers in India are now trying to pinpoint what is behind the unprecedented surge, which could be due to an unfortunate confluence of factors, including the emergence of particularly infectious variants, a rise in unrestricted social interactions, and low vaccine coverage. Untangling the causes could be helpful to governments trying to suppress or prevent similar surges around the world.

European countries such as France and Germany are also currently experiencing large outbreaks relative to their size, and nations including Brazil and the United States are reporting high infection rates at around 70,000 a day. But India’s daily totals are now some of the highest ever recorded for any country, and are not far off a peak of 300,000 cases seen in the United States on 2 January.

‘Ripple in a bathtub’

COVID-19 case numbers started to drop in India last September, after a high of around 100,000 daily infections. But they began to rise again in March and the current peak is more than double the previous one (see ‘Surging cases of COVID-19’).

“The second wave has made the last one look like a ripple in a bathtub,” says Zarir Udwadia, a clinician-researcher in pulmonary medicine at P D Hinduja Hospital & Medical Research Centre in Mumbai, who spoke to Nature during a break from working in the intensive-care unit. He describes a “nightmarish” situation at hospitals, where beds and treatments are in extremely short supply.

Shahid Jameel, a virologist at Ashoka University in Sonipat, agrees that the intensity of the current wave is startling. “I was expecting fresh waves of infection, but I would not have dreamt that it would be this strong,” he says.

Studies that tested for SARS-CoV-2 antibodies — an indicator of past infection — in December and January estimated that more than 50% of the population in some areas of India’s large cities had already been exposed to the virus, which should have conferred some immunity, says Manoj Murhekar, an epidemiologist at the National Institute of Epidemiology in Chennai, who led the work. The studies also suggested that, nationally, some 271 million people had been infected1 — about one-fifth of India’s population of 1.4 billion.

These figures made some researchers optimistic that the next stage of the pandemic would be less severe, says Ramanan Laxminarayan, an epidemiologist in Princeton University, New Jersey, who is based in New Delhi. But the latest eruption of COVID-19 is forcing them to rethink.

One explanation might be that the first wave primarily hit the urban poor. Antibody studies might not have been representative of the entire population and potentially overestimated exposure in other groups, he says.

The antibody data did not reflect the uneven spread of the virus, agrees Gagandeep Kang, a virologist at the Christian Medical College in Vellore, India. “The virus may be getting into populations that were previously able to protect themselves,” she says. That could include wealthier urban communities, in which people isolated during the first wave but had started mingling by the second.

Challenges That Lie in the Road Ahead

The biggest challenge in India’s fight against COVID-19 is the population, with a population density that is almost 3 times that of China. The scenario is potentially worse in urban slums where the population density may exceed more than 250 000/km2, making social distancing impossible. As many as 140 million people in India are migrant daily-wage laborers; with imposition of nationwide lockdown, they are being forced to flock back to their villages without being able to abide by government advisories of social distancing.17 Unfortunately, another major hurdle in India’s struggle against COVID-19 has been the attitude and action of some of the citizens; there have been occasional reports of civilians hiding travel history in an attempt to escape quarantine and people participating in otherwise forbidden massive religious gatherings.17,18 Although the health care infrastructure has been urgently strengthened and nearly 2000 dedicated COVID-19 facilities have been amassed all over the country over a short period of time,19 the dearth of doctors cannot be made up overnight. India has just 0.8 doctors per 1000 population as against Italy’s 4.1, China’s 1.8, Spain’s 4.1, Iran’s 1.1 and the United States’ 2.6.20 In addition, the eastern states of West Bengal and Odisha have recently been hit by a super cyclone named Amphan that have wreaked havoc in the 2 states. People stranded homeless by the natural calamity have been rescued and placed in cyclone shelters where social distancing is practically not possible.21

Silver Lining in the Dark Clouds

Certain factors, although hypothetical, do favor a limited spread of COVID-19 pandemic in India, notably, the ambient tropical temperatures, malarial endemicity, universal BCG (Bacillus Calmette-Guérin) vaccination, and the age-old Indian tradition of greeting by namaste as opposed to handshake. Of late, COVID-19 kits are being produced in the country itself by more than one manufacturer, thereby, reducing the cost of testing. Testing rates, though much lower than the developed nations, are at par with the neighboring developing countries, like Thailand, Indonesia, Myanmar, Philippines, and Pakistan.10 In addition, the proportion of people ≥70 years of age is only 3.3% in India,22 as against 11.9% in China and 37.6% in Italy,23 thereby, one could expect overall mortality rate to be low in India. Last, India is the largest producer (and supplier) of hydroxychloroquine in the world,24 the drug that has been found to have some benefit in COVID-19.25 Although some recent observational studies have found no benefit of hydroxychloroquine,26,27 proper randomized controlled trials are lacking. However, a recent study conducted among health care workers in India has shown that prophylactic consumption of 4 or more maintenance doses of hydroxychloroquine was associated with a significant decline in the odds of getting infected along with a favorable side effect profile.28

Conclusions

India is presently witnessing a rapid surge in the number of COVID-19 cases. Although the nationwide lockdown has been able to decelerate the spread, the country’s ever-increasing population, remarkably high population density and poor socioeconomic conditions are major barriers in India’s battle against COVID-19. However, the overall low case-fatality rate is reassuring. The Government of India and the health care providers have been relentless in their efforts. The citizens must also help support the fight against the pandemic by adhering to government advisories of containment and social distancing.

References:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7350042/

https://www.who.int/emergencies/diseases/novel-coronavirus-2019/question-and-answers-hub/q-a-detail/coronavirus-disease-covid-19

https://www.nature.com/articles/d41586-021-01059-y