Thread.

So what is the source of all this 'BCG vaccine for Corona' discussion?
BCG gives immunity agnst TB bacteria n other bacteria of same family. But coronavirus is, well, a virus.
There hasn't bn a single study on the topic. NYIT study is often quoted but is unpublished...

..So I decided to do some literature review. Here are some interesting findings:
1. BCG is shown to protect against wide range of microbes including some viruses.
2. The mechanism was investigated by Mihai Netea in 2018 in a remarkable study
3. BCG modifies histone proteins....

...in monocyte cells' genetic material. It is called epigenetic reprogramming.
4. Monocytes give innate immunity n r first line of defence. They do not require previous memory of the pathogen.
5. This modification 'supercharges' monocytes, it becomes killing machine.
However,...

...only the monocytes in circulation get this property. They have limited lifetime. So its long term effects are yet to be proven.

So, comparing Portugal with Spain coz one has BCG program other not, looks irrelevant. It also explains why not all BCG vaccined nations r doing...

...are doing well against Coronavirus. Because it likely has 'trained immunity' effect for limited time period. So, if BCG's 'trained immunity' is to be used against #Corona, fresh vaccinations may be required.
However, it'll b months b4 clinical trials conclude. till then
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