NEW DELHI >> When the coronavirus pandemic took hold in India, there were fears that it would sink the fragile health care system of the second most populous country in the world. Infections climbed dramatically for months and at one point India looked like it would overtake the United States as the country with the highest toll.
But infections began to decline in September, and now the country reports about 11,000 new cases a day, compared to a peak of nearly 100,000, which leaves experts confused.
They suggested many possible explanations for the sudden decline – seen in almost every region – including that some parts of the country may have reached herd immunity or that Indians have some protection against the virus.
The Indian government has in some cases also attributed the coverage to wearing a mask, which is publicly mandatory in India and carries major fines in some cities. But experts noted that the situation is more complicated because the deterioration is uniform, although the adherence to mask in some areas flag.
It’s more than just an interesting puzzle; to determine what is behind the decline in infections, authorities can help control the virus in the country, which has reported nearly 11 million cases and more than 155,000 deaths. About 2.4 million people have died worldwide.
“If we do not know the reason, you can subconsciously 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, misses many infections, and there are questions about how it counts virus deaths. But tensions in the country’s hospitals have also eased in recent weeks, further indicating that the spread of the virus is slowing. When recorded cases exceeded 9 million in November, official figures showed that almost 90% of all critical care beds in New Delhi were full. On Thursday, 16% of these beds were occupied.
The success can not be attributed to vaccinations, as India only started firing in January – but as more people get a vaccine, the prospects should look even better, although experts are also concerned about variants identified in many countries that looks more contagious. and make some treatments and vaccines less effective.
Some of the possible explanations for the fall in cases are that some large areas have reached herd immunity – the threshold at which enough people have developed immunity to the virus, by becoming ill or vaccinated, that the spread is starting to slow down, Vineeta Bal said. who studied immune systems at the Indian Institute of Immunology in India.
But experts have warned that even though the immunity of herds in some places is partly responsible for the decline, the population as a whole remains vulnerable – and must continue to take precautions.
This is especially true because new research suggests that people who become ill with one form of the virus may become infected again with a new version. Ball, for example, pointed to a recent survey in Manaus, Brazil, which estimated that more than 75% of people there had antibodies to the virus in October – before the incidence increased again in January.
“I don’t think anyone has the final answer,” she said.
And in India, the data is not that dramatic. A nationwide survey of antibodies by Indian health agencies has estimated that about 270 million, or one in five Indians, were infected by the virus before vaccinations began – this is well below the percentage of 70% or higher that experts say is the threshold for the coronavirus, although even this is not certain.
“The message is that a large part of the population is defenseless,” says Dr. Balram Bhargava, who heads India’s leading medical research body, the Indian Council of Medical Research.
But the survey provides other insights into why India’s infections may decline. It has shown that more people in India’s cities than in its villages are infected, and that the virus is moving more slowly through the rural interior.
“Rural areas have less density, people work more in open spaces and houses are much more ventilated,” said Dr. K. Srinath Reddy, president of the Public Health Foundation of India, said.
If some urban areas move closer to herd immunity – wherever the threshold is – and also limit transmission by masks and physical distance and thus see cases, the low speed at which the virus moves through rural India may help declining figures, suggests Reddy.
Another possibility is that many Indians are exposed to various diseases throughout their lives – for example cholera, typhoid and tuberculosis – and this exposure can help the body to get a stronger, initial immune response to a new virus.
‘If the COVID virus can be controlled in the nose and throat before it reaches the lungs, it does not become as serious. Congenital immunity works at this level by trying to reduce the viral infection and prevent it from reaching the lungs, ”said Jameel from Ashoka University.
Despite the good news in India, the emergence of new variants has added another challenge to efforts here and around the world to bring the pandemic under control. Scientists have identified several variants in India, including some that are blamed for causing new infections in people who already had an earlier version of the virus. But they are still studying the consequences for public health.
Experts are considering whether variants could cause an increase in cases in the southern state of Kerala, which was previously considered a blueprint to tackle the virus. Kerala is now responsible for almost half of the current COVID-19 cases in India. Government-funded research has suggested that a more contagious version of the virus may be playing out, and efforts to track its genome are continuing.
As the reasons behind India’s success are unclear, experts are worried that people will drop their hats. Large parts of India have already become normal again. In many cities the market is rising, the roads are full and the restaurants are almost full.
“With the decline in numbers, I feel the worst of COVID is over,” said MB Ravikumar, an architect who was hospitalized and repaired last year. “And we can all breathe a sigh of relief.”
Maybe not yet, said Jishnu Das, a Georgetown University health economist who advises the West Bengal state on dealing with the pandemic.
“We do not know if it will return after three to four months,” he warned.