Possible impact of BCG vaccine on COVID-19 mortality rate
Analyzing different aspect of correlation between BCG vaccination and COVID-19
mortality per capita (i.e. per 100000K population) in 134 world countries
Abstract:
BCG is the vaccine to prevent tuberculosis. Tuberculosis is caused by bacteria that attacks the lungs.
People contract it by being in close contact with an infected person as they sneeze or cough.
French scientists began developing the BCG vaccine in 1908 and the first human trials began in 1921.
The name BCG, Bacillus Calmette-Guerin, comes from the names of the two bacteriologists
involved: Albert Calmette and Camille Guerin.
The original BCG was derived from a virulent strain of M. bovis isolated from a cow.
The first BCG strain was developed at the Pasteur institute in 1921 from an attenuated strain of
Mycobacterium bovis. Over the course of decades several laboratories developed their own daughter
BCG strain (see link with image of the
BCG "family tree).
The BCG vaccine contains a live but weakened strain of tuberculosis bacteria that provokes the body to
develop antibodies to attack TB bacteria. This is called an adaptive immune response, because the body
develops a defense against a specific disease-causing microorganism, or pathogen, after encountering it.
Most vaccines create an adaptive immune response to a single pathogen.
Unlike other vaccines, the BCG vaccine may also boost the innate immune system, first-line defenses that
keep a variety of pathogens from entering the body or from establishing an infection. One study in
Guinea-Bissau found 50% lower mortality rates in children vaccinated with BCG than in kids who
did not get this vaccine. That is a much bigger drop in deaths than could be explained by a
reduction in TB cases. Some studies have found similar reductions in respiratory infections among
teens and the elderly. Those studies showing the BCG vaccine provided protection against not just
tuberculosis bacteria but also other types of contagions.
As of now, BCG also provides cross-protection against leprosy. Another common use of BCG is for the bladder
cancer treatment. Recently, Hebrew University researchers found that BCG may fight the sustained inflammation
that is a feature of Alzheimer’s disease.
Annotation for Analytics Dashboard provided below:
It was noticed by several institution (including Department of Biomedical Sciences at the New York
Institute of Technology’s College of Osteopathic Medicine) a direct correlation between COVID-19
mortality figures exhibited by countries with a mandatory BCG shot, and those where the vaccination is
optional. On Dashboard's top right sheet (below), you can hover or click mouse on each bar representing country and see its mortality
rate per 100K population. The same you can do on the map sheet (top left), as well as you can use the slider to see the mortality
rate that is more or less than average.
Red bars/country color represent the countries where it was no mandatory universal BCG vaccination.
Green bars/country color represent the countries where BCG mandatory vaccination still exists.
Blue bars/country color represent the countries where universal mandatory BCG vaccination existed in the past, but then
stopped.
For those countries there is another sheet (bottom left) where each bar represents the year
(in respective country) when mandatory vaccination was stopped. The mortality rate for such variation also
has some correlation in respect to the provided years.
Also, different countries use different BCG vaccination schedules, as well as different strains of the
bacteria, so the bottom right sheet depicts those differences in respect to COVID-19 mortality rate per
capita for each country. Difference in schedule means if country with universal vaccination had/has
multivaccination called boosters, i.e. when one or two vaccinations were mandated after the initial one.
The same sheet has some info pertaining to the strain that was used for BCG , though information about
that is quite limited (only for 16 countries). Among those strains the more virulent (so, more strong) is
the BCG Russia, then a bit less strong is the Tokyo172, and less strong is Danish.
References:
Countries with Mandatory Policies to BCG Vaccine Register Fewer Coronavirus Deaths
The BCG World Atlas
Mortality Analysis-Johns Hopkins University
Tuberculosis vaccine strain Mycobacterium bovis BCG Russia is a natural recA mutant
Novel genome polymorphisms in BCG vaccine strains and impact on efficacy
