Are there latitude, temperature or weather effects on Covid? Some early studies found associations. Now, a new possible explanation for cross-national variation: ”countries with TB vaccination programmes have far fewer coronavirus cases by a factor of 10.” https://www.irishtimes.com/news/health/coronavirus-more-striking-evidence-bcg-vaccine-might-protect-against-covid-19-1.4222110">https://www.irishtimes.com/news/heal...

“BCG has a specific target: TB. But evidence accumulating over the past decade suggests the vaccine also has so-called off-target effects, reducing viral illnesses, respiratory infections and sepsis, and appears to bolster the body’s immune system.” https://www.nytimes.com/2020/04/03/health/coronavirus-bcg-vaccine.html">https://www.nytimes.com/2020/04/0...

”A 25-year study of over 150,000 children in 33 countries — have reported a 40 percent lower risk of acute lower respiratory tract infections in children who received a B.C.G. vaccine.” https://www.nytimes.com/2020/04/03/health/coronavirus-bcg-vaccine.html">https://www.nytimes.com/2020/04/0...

”Not everyone is convinced. Dr Accili, an endocrinologist at Columbia, said efforts to use the vaccine against coronavirus sound ‘like magical thinking.’ While acknowledging BCG is ‘a non-specific booster of the immune system, we should be able to deploy a more tailored approach”

“We found that countries without universal policies of BCG vaccination (Italy, Nederland, USA) have been more severely affected compared to countries with universal and long-standing BCG policies.” https://www.medrxiv.org/content/10.1101/2020.03.24.20042937v1.full.pdf+html">https://www.medrxiv.org/content/1...