Thursday, February 18, 2021
Why did COVID fail to take off in India and has now collapsed? Mystery plunge in coronavirus
Scientists are trying to work out why coronavirus cases in India are falling when at one point it looked like the country might overtake the US as the worst-hit nation.
In September the country was reporting some 100,00 new cases per day, but that went into decline in October and is now sitting at around 10,000 per day - leaving experts struggling to explain why.
While the Indian government has been keen to put the apparent success down to its mask-wearing and social distancing laws, few believe these measures alone are responsible for the dip.
Instead, experts believe it may be down to the fact that India's largest cities have reached herd immunity, meaning the virus has moved to rural areas where it spreads slower and where cases and deaths are far less likely to be tested and logged.
A recent survey found 56 per cent of people in Delhi - the country's most-populous city - have Covid antibodies, which is likely to be an under-estimate with 70 per cent required for herd immunity.
Only around 20 per cent of deaths in India are medically certified - meaning 80 per cent do not have an official cause of death - with analysts warning the country may be under-counting its Covid fatalities by two or three times.
India also tests far less than developed nations, with medical experts warnings some states are relying on rapid lateral flow tests that give false-negative results.
The country also has a far younger population than many western nations - with an average age under 30 - and has far lower rates of obesity, which are both major factors in serious Covid infections and deaths.
Antibody surveys carried out in Mumbai, India's second-largest city, and Pune also showed antibodies in around 50 per cent of the population, The Times reported.
'The most densely-populated areas are already saturated and reaching the threshold of herd immunity, Giridhar Babu, an epidemiologist at the Public Health Foundation of India, told the paper.
'The virus has now spread to rural areas, but they are not so dense.'
Having a less-dense population means the virus spreads slower, which will naturally bring down daily case figures.
But with access to healthcare in rural India often lacking, it may also mean that many cases and deaths are going undetected.
Testing data for India shows that just 0.5 people per 1000 are swabbed each day - one of the lowest rates among countries that report such data.
More data released in September last year showed that people in rural areas are less-likely to be swabbed than those in cities - meaning that as the disease moves away from urban centres, the number of positive tests appears to decline.
The average number of tests carried out per day has also been falling across the whole of India since mid-December, which could also help to explain why positive test results have fallen.
And even those who are swabbed may be returning false-negative results, with doctors warning in September last year that many states are over-reliant on rapid lateral flow tests, which are unreliable.
Rijo John, a public health policy analyst, also warned that some states are failing to report which kind of tests are being used, further muddying the picture.
'More and more states are moving towards rapid antigen detection tests, which are known to have a high percentage of false negatives and not utilising the gold standard RT-PCR tests to full capacity,' he said.
'It should be made mandatory for all states to report the break[down] of different test types as well as the positives from these.'
Data also shows 80 per cent of Indians die at home, with no national requirement for a cause of death to be given before a body can be cremated or buried.
That has led experts to warn of a 'substantial' under-counting of deaths, with Dr Babu warning the true toll could be two or three times higher than the official count.
But others point to easing pressure on the country's hospitals as evidence that something other than an under-counting of cases and deaths in going on.
Some point to India's young population and relatively low rates of obesity as possible explanations.
The country has an average age of less than 30 with just 15 per cent of adults being overweight and 5 per cent obese, according to 2015 data.
By comparison, the US - which has been hardest-hit by Covid - has an average age of 38 with 32 per cent of adults overweight and 36 per cent obese.
Age and obesity are known to be two of the biggest factors increasing the likelihood that someone will fall seriously ill or die from Covid.
Other theories include that India has been dealing with less-virulent strains of the virus than those found in Europe, the US and parts of Africa.
India suspended all commercial flights in March last year, and while it has been operating 'travel corridors' since July, it has been quick to cut off routes to countries where dangerous new variants have emerged such as the UK.
That could have stopped the country suffering from spikes in infections like that seen in Britain after the so-called Kent Variant emerged, epidemiologists suggest.
Others believe that Indians, many of whom live in unsanitary conditions and suffer repeated waves of infections, have naturally resilient immune systems.
Jacob John, a prominent virologist at Christian Medical College in Tamil Nadu state, said: '[India suffers] dengue, chikungunya, malaria, typhoid, cholera, dysenteries, influenza, so the "innate immune system" is trained to be on high alert.'
The success cannot be attributed to vaccinations since India only began administering jabs in January, with just seven million out of the country's 1.3billion population jabbed so far.
Experts have cautioned that even if herd immunity in some places is partially 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 got sick with one form of the virus may be able to get infected again with a new version.
A recent survey in Manaus, Brazil, that estimated that over 75% of people there had antibodies for the virus in October - before cases surged again in January.
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Did the CDC Really Say We Need to Wear 2 Masks? Here’s What You Need to Know About Double-Masking
Throughout the course of this pandemic, there has been widespread confusion, misunderstanding, and anxiety about COVID-19—how it is transmitted, how dangerous it is, and how to protect yourself from it.
Now, the latest topic of debate is whether or not the Centers for Disease Control and Prevention recommend double-masking, and like other COVID-19 debates, misconceptions abound.
The use of masks as a simple infection control measure has become a controversial and polarizing issue. Now, a new push to wear not one, but two masks at once threatens to make it even worse. But does it even make sense?
Protective masks are a lightweight and easy tool for reducing the chances of spreading respiratory pathogens from one person to another. Illnesses (such as COVID-19) are caused by respiratory viruses and are transmitted by our breaths.
Thus, it makes sense that placing a filtering barrier in front of our respiratory orifices would reduce the spread of respiratory viruses.
Nearly every locality in the United States now mandates wearing masks in situations where you are exposed to other members of the public, and 96% of the population is willing to wear a mask when they leave the house or come into contact with other people, according to a survey taken in December 2020.
Despite this, the rate of known cases, hospitalizations, and deaths due to COVID-19 reached unprecedented levels this past fall. The rate of hospitalizations alone eclipsed the summer spike by a twofold factor.
The conclusion to draw from this is that masks may indeed help in certain situations, but on their own they simply were insufficient to stem the spread of the virus in the past few months.
We seem to be on the downward slope of the present spike, as cases and hospitalizations have been on a sustained decline since January, and deaths have begun trending downward more recently, but it likely has little to do with masks, since they have been so broadly accepted or already mandated in so many places since before the fall spike.
So if one mask isn’t working very well, why not wear two?
That is the conclusion many are drawing from the recent CDC study. To unpack this study correctly, we must first understand that the CDC was testing different ways of wearing masks to improve their performance—it was not simply testing the efficacy of double-masking exclusively.
Here’s what the CDC found. Unsurprisingly, when a mask is better fitted to a person’s face, fewer aerosols and particulates escape past it.
In a trial where a source (a person coughing or breathing) and a receiver (the person from which aerosols were measured) wore two masks (a cloth mask worn over a medical procedure mask) the receiver was exposed to 96.4% less aerosol.
On its own, this is an interesting finding, but is impossible to be generalized to a policy on how we ought to comport ourselves during the present pandemic.
One problem is that this study only tested one type of procedure mask and one type of cloth mask. Procedure masks are fairly standard (although there are different strap types), but the market for cloth masks includes an endless variety of fabrics and forms.
Outside of the ideal conditions of a laboratory, someone who opts to wear a cloth mask on top of a procedure mask would lose all the benefits of improved filtration if, for example, the cloth mask was poorly fitted to the face.
If, for instance, a cloth mask has poor fitment, it would do nothing to improve filtration, and the purpose of the double mask would be negated.
Another problem is that the aerosols in the experiment are not an exact representation of viral particles, but of a person’s respirations. How infectious a person’s respirations are would depend on his or her viral load.
Thus, a reduction in exposure, as measured in the study, does not necessarily mean the same reduction in infectiousness.
The study authors themselves recognize that these findings are not to be interpreted “as being representative of the effectiveness of these masks when worn in real-world settings.”
Indeed, to reduce the point of the study as to simply a trial of the effects of double-masking would be far too narrow an interpretation—in reality, the results only speak to the effectiveness of the particular masks used.
As every person has a unique face, masking, double-masking, or other modified mask-wearing could all work to varying degrees. The only true conclusion from this study is not that we should all wear two masks, but that better fitting masks filter our breaths better.
To that end, wearing a properly fitted N95 respirator would do just as well as double-masking, or rather, better.
The greatest potential utility of masks is when people who are possibly exposed find themselves in situations where physical distancing from strangers is impossible—for instance, while walking past others in a grocery store aisle.
But masks were only ever meant to be part of a broad mitigation strategy. They were never meant to seal us off from the dangers of the world.
If people want to wear two masks, they should certainly do so, but everyone must remember that masks only make up one part of a broader mitigation strategy, which includes assessing risks, social distancing, testing, and importantly now, vaccinating. Policymakers should remember this, rather than rely on masks and make them even more unappetizing to use.
And policymakers should explore additional options—like widespread rapid self-testing, which is an even more promising way to battle the pandemic.
It has been over a year now since SARS-CoV-2 first arrived on our shores, and Americans have been asked to avoid buying masks, to wear masks, and, now, to wear two masks.
We’ve learned many things over the course of 2020, but at no point did we learn that masks would be anything other than an adjunct to better, more effective measures.
Doubling up on masks, at this point, would be doubling down on one of the least effective measures we now have.
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Also see my other blogs. Main ones below:
http://snorphty.blogspot.com (TONGUE-TIED)
http://edwatch.blogspot.com (EDUCATION WATCH)
http://antigreen.blogspot.com (GREENIE WATCH)
http://pcwatch.blogspot.com (POLITICAL CORRECTNESS WATCH)
http://australian-politics.blogspot.com/ (AUSTRALIAN POLITICS)
http://awesternheart.blogspot.com.au/ (THE PSYCHOLOGIST)
https://heofen.blogspot.com/ (MY OTHER BLOGS)
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