Are Indians more immune to Covid-19?(bbc.com) |
Are Indians more immune to Covid-19?(bbc.com) |
It is indeed very interesting and worthy of consideration that Indians and other people from poor countries with lesser hygiene may be more immune to COVID infections.
India's government lifted its infamous lockdowns at times when the number of active cases only seemed to be flying upwards and had no anticipations of coming down anytime soon. In a poor, extremely overpopulated country with high rates of overcrowding and very low hygiene standards, coupled with rampant unemployment and economic distress, anyone could have only expected the situation to worsen. And it did - the country's GDP shrunk by almost a quarter and cases continued to pile up... until they didn't. The number of active cases miraculously peaked mid-November and have been in a healthy downward trend since. While developed countries like the UK seem to have their number of active cases shoot up exponentially, many states in India are experiencing a net decrease in cases to very safe levels. Even infamously overcrowded states like Uttar Pradesh are displaying impressive levels of recovery.
One has to reckon there must be something more to it than just government interventions and change in attitudes.
Having said that, there's molecular biological evidence of cross immunity to other forms of coronavirus so there might very well be something to it.
I've wondered along these lines if keeping kids out of schools might in some ways be counter productive, by decreasing exposure to other coronaviruses or other pathogens that increase immunity.
I've often wanted to see if, eg, parents of young children, or people working with young children (teachers, pediatricians, etc) have less severe outcomes from sars-cov-2 than matched controls.
About 28% of the Indian population has been infected (15-22% according to more pessimistic estimates). In some areas it's even higher, 41% in the slums of Mumbai.[1] The virus is running out of hosts. That is not a miracle, it's completely expected.
[1] https://www.sciencemag.org/news/2020/10/indias-covid-19-case...
Typo? We're not mid-November yet.
Is it the vitamin D? We should really try to figure out why these regions have done so well and try to replicate that in Europe and NA.
can provide more sources if requested (or just google it)...
Latin America seems to be all over the list of top deaths/capita for the whole pandemic, but currently the worst places (per capita deaths in the last 7 days) seems to be mostly central/eastern europe, though Argentina is pretty high in both all time and recent deaths/capita.
Where Africa is doing well or just doesn't have good surveillance to even identify cases, I couldn't say. But if a place doesn't have much inbound tourism, doesn't have lots of people able to afford international travel, and doesn't have the kind of internal mobility common in the developed world, it would make sense that they might not get hit very hard without taking much in the way of special precautions.
https://www.immunology.org/public-information/bitesized-immu....
"As the name suggests regulatory T cells (also called Tregs) are T cells which have a role in regulating or suppressing other cells in the immune system. Tregs control the immune response to self and foreign particles (antigens) and help prevent autoimmune disease. Tregs produced by a normal thymus are termed ‘natural’. Treg formed by differentiation of naïve T cells outside the thymus, i.e. the periphery, or in cell culture are called ‘adaptive’."
In this case, it might be a matter of exposing the immune system to more pathogens so that it doesn't freak out when it sees them:
"In medicine, the hygiene hypothesis states that early childhood exposure to particular microorganisms (such as the gut flora and helminth parasites) protects against allergic diseases by contributing to the development of the immune system. In particular, a lack of exposure is thought to lead to defects in the establishment of immune tolerance. The time period for exposure begins in utero and ends at school age."
https://en.wikipedia.org/wiki/Hygiene_hypothesis
The immune system self-regulates. Otherwise it would constantly be freaking about about every food you eat or every particle in the air you breathe in or whatever. One of the primary issue with coronavirus is the cytokine storm resulting from the immune system freaking out, and one of the most effective front-line treatments is steroids to knock-down the immune system. So, by letting kids sneeze on each other and play in the mud and catch all the colds and stuff, you're allowing their immune system to develop 'tolerance' to benign stuff in the environment. There may be something like that at play here.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7365923/ Tang Y, Liu J, Zhang D, Xu Z, Ji J, Wen C. Cytokine Storm in COVID-19: The Current Evidence and Treatment Strategies. Front Immunol. 2020;11:1708. Published 2020 Jul 10. doi:10.3389/fimmu.2020.01708
"They define that “cytokine storm” is an activation cascade of auto-amplifying cytokine production due to unregulated host immune response to different triggers. The triggers involved infections, malignancy, rheumatic disorders, etc."
Yeah, so cytokines are just immune system signaling molecules. For some reason, Coronavirus causes the immune system to completely lose it's shit in some people. So, it's theoretically plausible that the more coronaviruses (common colds) you were exposed to as a kid, the less your immune system will overreact because it's seen something similar before many times.