NEW DELHI (AP) – 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 it looked like India would overtake the United States as the country with the highest toll.
But infections started to decline in September, and now the country is reporting about 11,000 new cases a day, compared to a peak of nearly 100,000, leaving experts perplexed.
They have provided many possible explanations for the sudden decline – which can be seen in almost every region – including that some parts of the country may have achieved immunity to herds or that Native Americans have some pre-existing 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 decline is uniform, although mask adherence is declining in some areas.
It’s more than just an intriguing puzzle; By determining what’s behind the decline in infections, authorities can get the virus under control 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 trigger 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 deathsBut pressure on the country’s hospitals has also eased in recent weeks, another indication that the spread of the virus is slowing. When recorded cases exceeded 9 million in November, official figures showed nearly 90% of all intensive care beds with ventilators in New Delhi were full. On Thursday 16% 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 brighter, although experts are also concerned about variants found in many countries have been identified that appear to be more contagious and make some treatments and vaccines less effective.
One possible explanation for the decline in cases is that some large areas have reached herd immunity – the threshold at which enough people have developed immunity to the virus, either by getting sick or being vaccinated, that the spread begins to decline. Vineeta Bal said. who studies immune systems at the Indian 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% of people there had antibodies against the virus in October – before cases rose sharply 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, were infected with the virus before vaccinations began – that’s well below the 70% or higher rate that experts say crossed 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 less 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 flows through rural India might help. explain declining figures, suggested Roodje.
Alternatively, many Indians may be exposed to a variety of diseases 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 be 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 efforts are underway to sequence the genome.
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.
The Associated Press Department of Health and Science is supported by the Science Education Department of the Howard Hughes Medical Institute. The AP is solely responsible for all content.