NEW DELHI – When the coronavirus pandemic hit India, there were fears it would sink the fragile health system of the world’s second most populous country. Infections increased dramatically for months and at one point India looked like it was going to overtake the United States as the country with the highest toll.
But infections started to plummet in September, and now the country is reporting about 11,000 new cases per day, compared to a peak of nearly 100,000, leaving experts perplexed.
They have provided many possible explanations for the sudden decline – seen in almost every region – including that some parts of the country may have achieved immunity to herds or that Native Americans already have some protection against the virus.
The Indian government has also attributed the slump in business in part to the wearing of masks, which is publicly mandated in India and violations lead to hefty fines in some cities. But experts have noted that the situation is more complicated because the deterioration is uniform, although mask adherence is declining in some areas.
It’s more than just an intriguing puzzle; Determining what’s behind the drop in infections could help authorities control the virus in the country, which has reported nearly 11 million cases and more than 155,000 deaths. Worldwide, about 2.4 million people have died.
“If we don’t know the reason, you could unconsciously do things that could lead to a flare-up,” says Dr. Shahid Jameel, who studies viruses at Ashoka University in India.
India, like other countries, lacks a lot of infections and there are questions about how it counts virus deaths. But pressure on hospitals in the country has also eased in recent weeks, another indication that the spread of the virus is slowing. When the number of recorded cases exceeded 9 million in November, official figures showed that nearly 90 percent of all intensive care beds with ventilators in New Delhi were full. On Thursday, 16 percent of these beds were occupied.
That success cannot be attributed to vaccinations, as India only started giving injections in January – but as more people get a vaccine, the outlook should look even better, although experts are also concerned about variants found in many countries have been identified and appear to be more contagious. and make some treatments and vaccines less effective.
One possible explanation for the drop in the number of cases is that some large areas have reached herd immunity – the threshold at which enough people have developed immunity to the virus, by getting sick or being vaccinated, that the spread is starting to decrease. , said Vineeta Bal, who studies immune systems at India’s National Institute of Immunology.
But experts have warned that even if herd immunity is partly responsible for the decline in some places, the population as a whole remains vulnerable – and must continue to take precautions.
This is especially true because new research suggests that people who have fallen ill with one form of the virus could potentially become infected again with a new version. For example, Bal pointed to a recent study in Manaus, Brazil, which estimated that more than 75 percent of people there had antibodies to the virus in October – before cases spiked again in January.
“I don’t think anyone has the definitive answer,” she said.
And in India, the data is not that dramatic. A nationwide antibody screening by Indian health authorities estimated that about 270 million, or one in five Indians, had been infected by the virus before vaccinations began – that’s well below the 70 percent or higher rate that experts say reached the threshold for the coronavirus. although even that is not certain.
“The message is that much of the population remains vulnerable,” said Dr. Balram Bhargava, head of India’s leading medical research agency, the Indian Council of Medical Research.
But the survey offered a different insight into why infections in India could be declining. It showed that more people were infected in the cities of India than in the villages and that the virus spread more slowly through the rural hinterland.
“Rural areas have fewer crowds, people work more in open spaces and houses are much better ventilated,” says Dr. K. Srinath Reddy, President of the Public Health Foundation of India.
If some urban areas get closer to herd immunity – wherever that threshold is – and also limit transmission through masks and physical distances and thus see declining cases, the slow speed at which the virus is flowing through rural India may help. explain declining figures, suggested Roodje.
Alternatively, many Indians may be exposed to a variety of illnesses throughout their lives – cholera, typhoid, and tuberculosis, for example, are common – and this exposure can stimulate the body to build a stronger initial immune response against a new virus. .
“If the COVID virus can be controlled in the nose and throat before it reaches the lungs, it won’t get that serious. Innate immunity works at this level by trying to reduce viral infection and keep it from entering the lungs, ”said Jameel of Ashoka University.
Despite the good news in India, the emergence of new variants has added a new challenge to efforts here and around the world to get the pandemic under control. Scientists have identified several variants in India, including some blamed for causing new infections in people who already had an earlier version of the virus. But they are still studying the implications for public health.
Experts are considering whether variants could lead to an increase in the number of cases in the southern state of Kerala, which was previously hailed as a blueprint for tackling the virus. Kerala now accounts for nearly half of the current COVID-19 cases in India. Government-funded research has suggested that a more contagious version of the virus could be at play, and genome sequencing is underway.
As the reasons behind India’s success are unclear, experts are concerned that people will lower their guard. Large parts of India have already returned to normal life. In many cities, the markets are busy, the roads are busy and restaurants almost full.
“With the numbers declining, I feel like the worst of COVID is over,” said MB Ravikumar, an architect who was hospitalized and recovered last year. “And we can all breathe a sigh of relief.”
Maybe not yet, said Jishnu Das, a health economist at Georgetown University who advises the state of West Bengal on how to deal with the pandemic.
“We don’t know if this will come back after three to four months,” he warned.