Updated: October 1, 2020 10:35:34 pm
The case count in Himachal is now 14,252, including 3,501 active cases, 174 deaths and 10,552 recoveries.
A first such study of the coronavirus epidemic in India suggests that an overwhelming number of infected people – more than 70 percent – may not be transmitting the virus to other people. The disease could spread only through a small group of infected people.
A study published in the journal Science has drawn on data from more than 85,000 confirmed infections in Andhra Pradesh and Tamil Nadu as of August 1, and nearly six lakh of their contacts who were identified and traced, the largest study of its kind. anywhere in the world. It has been found that no infection was detected in the contacts of nearly 71 percent of confirmed positive cases. In other words, more than 60,000 of the infected people did not transmit the disease to anyone.
But a small group of infected people, less than 10 percent, accounted for up to 60 percent of secondary information. These were the individuals who transmitted the virus to 20, 30 or 40 others.
The study also found that transmission of the virus was more effective in the same age groups. This was especially true among children and the elderly.
Crucially, it was found that the death rate among the elderly was not as high as in some other developed countries like the United States. Women among the older population were found to have significantly lower mortality than men.
“Some of these findings are not very surprising. The fact that only a few people are primarily responsible for the spread of the disease, for example. It is quite well established for other infectious diseases. It’s called the 80:20 rule. About 20 percent of infected people are responsible for about 80 percent of secondary infection. This study shows that this also appears to be true for the current epidemic in India, ”said Gautam Menon, professor of physics and biology at Ashoka University.
An important reason for this is that a large number of infected people, at least those who have been detected or who have symptoms, isolate themselves and do not come into contact with other people. But there could also be biological reasons.
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“Some people tend to shed a higher viral load and, therefore, have a greater capacity to infect. But of course, you also need to interact with people to infect them. Isolation reduces that opportunity. So it’s a combination of both, ”Menon said.
The small group of ‘super-spreaders’ are usually people who are unaware of their infected status and who interact with large numbers of people in their regular work, such as vegetable sellers or street vendors, for example. In fact, the Koyambedu market group in Chennai was responsible for transmitting the disease to thousands of people, who then carried the disease to far-flung districts of Tamil Nadu.
Menon said the study’s most interesting finding was the relatively low death rate among older populations compared to the United States and countries in Europe. The study reported that the case fatality rate, or the percentage of people who died who were confirmed to be infected, was 9.58% in the 65-74-year-old group, and 13% in the 75-year-old group. 84 years. and 16.6% for the elderly. At all ages, the fatality rate of 2.06%. While older people were more vulnerable, they were less so compared to their counterparts in other countries.
“In the United States and European countries, the number of fatalities increases considerably in the groups of 65 years and over. That doesn’t seem to be happening here, which is very revealing. Because if this is true, it conveys something very interesting about the nature of the disease in the Indian population. There has been all this debate about whether we are accurately reporting our death figures. Assuming these data are correct, I think this is extremely significant, ”he said.
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One of the possible reasons, as also suggested in the study, could be that people who survive longer in India tend to be in better condition, socially and economically, and have much better access to health services. This phenomenon is more pronounced in India than in other countries, according to the study.
Older women had death rates several percentage points lower than men. In the 65-74 age group, for example, the CFR in women was 6.67% compared to 11.5% in men. Similarly, in the 75-84 age group, women had a conversion rate of 8.56 percent, while men had 16 percent. In the still older group, women had a mortality of only 11.1%, while men had 20.5%.
The finding of more widespread transmission in the same age groups could have implications for the reopening of schools and the resumption of student activities.
“This is the first time that we have data showing that children are not only suspected of infection, but could also be spreading the infection. As we begin to reopen schools and begin student activities, these things need to be taken into account. Also the fact that the study has found a higher probability that the infection spreads in small closed spaces than in open spaces. So school buses and crowded classrooms can be considered risky, ”said Shahid Jameel, director of the Trivedi School of Biosciences at Ashoka University.
Jameel was referring to the study’s finding that nearly 80 percent of people who had traveled with an infected person in a vehicle had become infected.
What the study finds
Transmission
- 71 percent of infected people did not infect anyone
- Increased risk of infection when people travel together in the same vehicle. Of 79 study contacts who had traveled with infected people, 63 became infected
- More efficient transmission in similar age groups. Most of the children contracted the infection from other children. It is also true for the elderly
Mortality
- Half of the deaths occurred within six days of the test.
- The elderly population is less vulnerable than in other countries
- Women less vulnerable than men
- Most common comorbid disease of diabetes, followed by sustained hyperactivity
- blood pressure, coronary artery disease and kidney disease
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