If I were North American/West European/Australian, I would take BCG vaccination now against the novel coronavirus pandemic.
I declare that there is no conflict of interest for BCG vaccination but I have a big interest in stopping this pandemic. One of my businesses is an online tourism agency and its sales have dried up!
1) Scientists started to work on this hypothesis
Immune boost against the coronavirus
2) If you look at the map displaying BCG vaccination policy by country, there seems to be a correlation to the speed of coronavirus spread and its spread among young people.
- The spread speed is fast in Italy and western Europe and the U.S. while the spread speed among Russia, eastern European countries, and Asian countries except Wuhan city is slow.
- In Asian countries, there are few young infected people or almost zero serious cases among young people. However, in western Europe and the U.S., there are cases among young people.*
- In Western Europe, you can compare Italy vs Croatia, Spain vs Portugal**, UK vs Ireland, Sweden vs Norway, ex-West Germany vs ex-East Germany. In the former countries, BCG vaccine is not mandatory while in the latter countries, BCG vaccine is mandatory. Now, you can compare the U.S. and Mexico.
- I live in Tokyo and Brisbane. Though the normal social distance is much longer and less crowded in Brisbane and the government policy is 10 times stricter, the spread speed is faster in Brisbane than in Tokyo.
(Added on 29 Mar)
A reader told me there is an article (not yet certifed by peer review)
The article has this chart. I believe if we can adjust for the timing of coronavirus spread, the correlation would be even higher.
(Added on 30 Mar)
In the world map above, Canada is in orange and categorized in C: The country never had universal BCG vaccination programs. However, if you look at Canada in http://www.bcgatlas.org/, it seems that Canada had a "routine" BCG vaccination program until 1960s-1970s (Please correct me if I read wrongly). This means people elder 60s mostly vaccinated! This may be the reason why Canada has a low death rate compared with the U.S. And Canada used BCG Tokyo strain.
One more weak fact. In Canada, people elder than 60s had BCG vaccine while people younger than 50s had not. Then, look at the age distribution of COVID-19 cases in Canada. Skew to people younger than 50s?! But infection rate may not vary by age, only hospitalization/ICU/death rate may vary by age. I'm looking for that data for Canada.
* I couldn't find good stats on this. Only anecdotal news stories. Eg. Greta Thunberg got infected by the novel coronavirus. Well, she is Swedish and born in 2003. Sweden stopped BCG vaccination in 1975.
** Among West European countries that had/have universal BCG vaccination program, Spain and Portugal are (one of) the last countries introduced it in 1965. And Spain is (one of ) the first country to stop it in 1981 and Portugal stopped it in 2017. Portuguese elder than 55 may have low BCG vaccination rate, which may result in high death rate than the other western Europe, but probably better than Spain.
3) There are several strains of BCG vaccination and Soviet/Japan/Brazil strains may be the most effective against the novel coronavirus.This comment by Tiger Paw sounds most plausible regarding the country differences though the article itself is worthless.
* The comment was deleted for some reason. The initial idea of this section attributes to Tiger Paw. If I hadn't read his comment, I would not know there are multiple types of BCG vaccine.
High-level impression; BCG Brazil, BCG Russia/Bulgaria, BCG Japan countries may immune to novel coronavirus. Countries that use more than one BCG vaccine strain look immune, too. BCG Brazil, BCG Russia/Bulgaria, BCG Japan are categorized in "I" and this may be the effective strain category.
Then, I looked into how BCG strains are categorized. I found the chart below. BCG Russia/Japan/Moreau(Brazil) are the first generation of the BCG vaccines.
While Iraq uses the Japan strain, Iran uses different strains. According to http://www.bcgatlas.org/ Iran had used its local (original?) BCG vaccine from 1947 to 1984 and make it compulsory in 1984. This means elderly people in Iran have less BCG vaccinated and for those who had it had a local(original?) BCG vaccine. Please check and compare Iraq and Iran figures. You will be surprised to see how different they are.
(Iran: 27 deaths per million, Iraq: 0.9 deaths per million as of 27 Mar; added)
BCG Japan(Tokyo) looks working quite well against the novel coronavirus. 1) Japan, Thailand, Taiwan, and Iraq have used BCG Tokyo and all of them have low death rates though they are close to China or Iran. 2) And so far, it is not reported that any Japanese got severely infected or died in Italy or Western Europe. 3) In Japan, there are 1,349 cases reported, and 934 are Japanese and 415 are non-Japanese. Hmm, quite a high ratio of non-Japanese (as of 28 Mar).
The website below seems to have a lot of information about BCG vaccination though this is not perfect, either.
I am afraid that I cannot digest this detailed medical information. Expert explanations will be welcomed.
I live in Tokyo and Brisbane and have been wondering why the spread speed is faster in Australia than Japan.
Tokyo is a very crowded city and it's impossible to keep the social distance. I expected a high speed of spread but the actual speed is low so far (though it's beginning to explode).
4) Deaths and severe cases skew to people who probably have not BCG vaccinated.
In Japan, all babies since 1951 have BCG vaccination and the coronavirus deaths in Japan are skewed drastically to the elderly born before 1951. 44 out of 45 deaths happen to those older than 70 (as of 26 Mar, https://toyokeizai.net/sp/visual/tko/covid19/).
(Added on 30 Mar)
This can be one of the critical supporting facts for this BCG vaccine hypothesis. Below is a death rate of COVID-19 in Spain by age group. You can see a higher death rate in 10s and 20s than the 30s or 40s. Spain had a universal BCG vaccination program from 1965 to 1981, which means from 39 to 55 years old had a BCG vaccine. Well, you can see a little higher rate in the 10s and 20s. It is a very unusual pattern from what we learned from China. Yes, the absolute numbers may be small and not statistically significant. But this is a sign!
5) BCG vaccination has a long history and there seems no little downside to human beings.
(Added on 28 Mar)