BCC vaccinated generation of Swedish has a lower relative death rate + Norway & Finland
A preprint denying the BCG hypothesis with the data of SwedenHere comes another preprint denying the BCG hypothesis by comparing age group in the same country, Sweden, this time. This method is flawed as it ignores the external immunity effect which is much larger than the individual immunity effect.
The BCG vaccine does not protect against COVID-19. Evidence from a natural experiment in Sweden
This preprint concludes that the BCG vaccine has no effect against COVID-19 since there is no difference in cases per 1,000 inhabitants before and after 1975 when Sweden stopped its universal BCG vaccination program.
However, this preprint also says it is hard to conclude from the death tolls as the mortality rate increases by age. Here is the figure of this preprint about the deaths per 1,000 inhabitants. Please look at this carefully.
Don't you notice that the mortality rate is not changing from 1972 to 1978 birth year? Isn't it strange? The mortality rate should be decreasing dramatically for the younger generation. Let's look at the mortality rate closely.
Comparing with Italy, BCC vaccinated generation of Swedish has a lower relative death rateWhile I strongly insist that all analysis should consider the external immunity effect reading my previous post, I will examine if the BCG vaccine has the individual immunity effect for Swedish people who were BCG vaccinated as I did it for Israel.
As the preprint stated, Sweden had its universal BCG vaccination program from the 1940s to 1975. This means that from Swedish who are from 45 to around 75 years old were BCG vaccinated.
I categorize the age groups into 0-39 (non-BCG), 40-79 (mostly BCG), 80+ (non-BCG), and compare Sweden with Italy where BCG vaccination has never been compulsory.
Firstly, the below chart is deaths per 1M population by the age group. While the total death per 1M population is 534 for Italy and 480 for Sweden, the death rate for 80+ is higher in Sweden. This may be partially due to the failure to protect aging care facilities in Sweden. Another reason is that the percentage of 90+ among 80+ in Sweden is a little higher than that in Italy.
The second chart is relative deaths per 1M pop by age group, setting 80+ death per 1M population to 100 to compare the age group difference relatively as most of 80+ in Sweden or Italy have not been BCG vaccinated.
And the third chart is the one setting not only 80+=100 in both countries but also all age groups in the Italy =100. You can see a big drop in 40-79 Swedish.
BCG vaccinated generation (from 45 - around 75 years old) of Swedish has lower relative death rate comparing with Italy. This fact validates the BCG hypothesis.
However, I would like to emphasize that the external immunity effect is far larger than the individual immunity effect. When we analyze epidemiologic data, design clinical trials, estimate R0, etc, we should put importance on the external immunity effect.
- Norway: mandatory at birth from 1947 to 2009 for 62 years. Denmark strain.
- From 11 to 73 years old were vaccinated.
- Finland: mandatory at birth from 1941 to 2006 for 65 years. Denmark strain.
- From 14 to 79 years old were vaccinated.
- Sweden: voluntary but universally at birth from the 1940s to 1975 for 30 years. Sweden strain(?)
- From 45 to 75 years old were vaccinated.
- The death rates for Norway and Finland that have much wider BCG coverages are significantly lower than for Italy and Sweden.
- The relative death rates are lower for the generations who had BCG vaccination for Sweden, Norway, and Finland.
- The death rates of Norway and Finland that have a similar BCG history have a similar death rate pattern by age groups.