Is the sharp drop in coronavirus cases in India as dramatic and curious as some believe?
Is the epidemic steadily receding in a country where many early modelers predicted millions of deaths due to Covid-19?
In October, I wrote extensively about why the epidemic seemed to be subsiding in India. Cases reached a record high in mid-September – there were more than a million active cases. After that, daily deaths and the number of cases began to decline, despite consistent testing and some short and violent spikes in infections in cities like Delhi.
The situation has improved remarkably since then.
In the middle of last week, India barely counted an average of 10,000 cases of Covid every day. The seven-day average of daily deaths from the disease has dropped to less than 100. More than half of India’s states have reported no deaths in Covid. On Tuesday, Delhi, once a hot spot for infection, did not report a single death from Covid, for the first time in 10 months.
So far, India has registered more than 10 million infections – the second largest in the world after the USA. There have been more than 150,000 deaths reported by the disease. The death toll per million people is 112, much lower than what has been reported in Europe or North America. It is also clear that the decline in cases is not due to lower tests.
Most pandemics generally go up and down in a bell-shaped curve. India was no exception. In addition, there was a high proportion of cases and deaths of people over the age of 65 living in densely populated cities, following infection trends around the world.
“There is nothing unusual about falling infections in India. There is no miracle here,” said Dr. Shahid Jameel, a leading virologist.
Experts say there is no dearth of possible causes – explained below – for the relatively low severity of the disease and its toll.
“We still have no causal explanations. But we know that India as a nation is far from collective immunity,” said Bhramar Mukherjee, a professor of biostatistics and epidemiology at the University of Michigan who closely follows the pandemic. Herd immunity occurs when a large part of a community becomes immune to a disease through vaccination or the mass spread of the disease.
Why is India far from achieving collective immunity?
The latest sero research – studies that detect antibodies – suggests that 21% of adults and 25% of children have already been infected with the virus.
He also found that 31% of people living in slums, 26% of urban non-slum populations and 19% living in rural areas were exposed to the virus. This is well below 50% – a number reported by some major cities, such as Pune and Delhi. Here, there is evidence of much higher levels of exposure to the virus, suggesting that these sites are probably closer to collective immunity.
But experts say the numbers are still very low.
“There is no region in the country that can be considered to have achieved collective immunity, although there may be small pockets,” said Dr. K. Srinath Reddy, president of the Public Health Foundation of India, a think tank based in Delhi.
Therefore, people who have not yet been exposed to the virus in places with a high prevalence of infection can remain protected in their communities, but would become vulnerable if they traveled to areas where transmission levels are lower.
So why are the cases decreasing?
Experts say there could be several reasons.
On the one hand, India saw a patchwork pandemic with cases increasing and decreasing at different times in different parts of the country.
More people were infected in cities – especially in crowded slums – and in developed urbanized districts than in smaller towns or villages. In all of these places, exposure to the virus varied significantly. Cases have now declined in most urban areas, but rural India still remains somewhat of a mystery.
“My guess is that exposure to infection is much higher than research indicates. Nor should we consider India as one. In some cities like Delhi, Mumbai, Pune and Bangalore, up to 60% of people have been found with antibodies to the virus, so everything is very uneven “, says Dr. Shahid Jameel, a leading virologist.
The other explanation is that India has lost and continues to lose many cases, mainly because a large number of infected people have no symptoms or have a very mild infection.
“If we had a large number of very mild or asymptomatic cases, we could have already reached a limit of collective immunity. If that is the case, we still have to explain, why were so many Indian cases so mild?” asks Partha Mukhopadhyay, senior researcher at the Policy Research Center in Delhi, who has studied the pandemic.
Is the low mortality rate a mystery?
Most scientists believe that many more Indians died from the infection than official figures reveal. India has a poor record of certificate deaths and a large number of people die at home.
But even this scale of underreporting has not caused public panic or overburdened hospitals. Consider this. India has about 600,000 villages. Even an undiagnosed and unreported death from Covid in every village every day would not burden the public health system.
India imposed a broad and early stoppage in late March to stop the spread of the virus. Scientists believe the shutdown, which lasted nearly 70 days, prevented many infections and deaths.
Transmission has slowed in the affected cities because of the expansion in the use of face masks, physical distance, school and office closings and people working at home.
Scientists also attributed fewer deaths to a young population, protective immunity, a vast rural population with insignificant links to cities, genetics, poor hygiene and ample protective lung protein.
Several studies claim that the infection is widely spread by the virus that floats indoors, small droplets suspended in stagnant air in poorly ventilated environments.
However, more than 65% of the Indians live and work in the fields. Brazil, for example, is almost three times more urbanized than India, and that could partly explain the high number of cases and deaths there, say the scientists.
In cities, the overwhelming majority of India’s workforce is involved in the informal economy. This means that many of them, such as bricklayers or street vendors, do not work in closed spaces. “The risks of transmission are less for people who work in open or semi-closed ventilated spaces,” says Dr. Reddy.
Did India avoid a second wave?
It is too early to say.
Some experts fear that India may have an outbreak of infections with the onset of monsoons, which also marks the beginning of the flu season in the country. It lasts from June to September and causes flooding across South Asia every year.
“The start of the next monsoon season will be critical. We can only make an informed assessment of whether the pandemic has really run its course in India after the season is over,” said an epidemiologist who declined to be named.
The real elephants in the room, the scientists say, are the new variants of the virus identified in South Africa, Brazil and the United Kingdom.
As a large number of Indians have not yet been exposed to Covid-19, a dominant strain could easily travel to relatively uninfected areas and trigger further outbreaks.
India reported more than 160 cases of the UK variant by the end of January. It is not clear whether the other variants are already circulating in the country. India could also easily have homemade variants.
The UK variant was detected in Kent in September, but it became the reason for a second full wave just two months later. It has since been found in more than 50 countries and is now set to become the dominant variety in the world.
India has enough scientific laboratories, but genome sequencing is still irregular, say the scientists.
“The history of the variant is a great one. It can disrupt all of our calculations. We need to be very vigilant and our laboratories must scale up the genome sequencing to look for variants,” said Dr. Jameel.
Clearly, India needs to speed up its vaccination campaign – about six million vaccines were applied in just under a month. The government plans to inoculate 300 million people by August to ensure that a second wave does not result in widespread infections.
And there is no room for complacency yet – doctors and scientists are asking people to avoid mass meetings and crowded areas, and continue to wear a face mask and practice hand hygiene.
Shadab Nazmi Graphics