BCG vaccination gives immunity against coronavirus: truth and fiction

At the end of March, when the epidemic Covid-19 spread worldwide, and the number of confirmed cases began to be measured in the hundreds of thousands, many drew attention to the suspicious coincidence, the BBC reports.

Прививка БЦЖ дает иммунитет от коронавируса: правда и вымысел

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In different States the disease is spreading at different speeds. And for some reason coronavirus — at least at first glance — exhibits significantly less activity in countries where children are mandatory vaccinated against tuberculosis with BCG vaccine, including in Russia.

What is it — a coincidence? Or is there some kind of pattern?

Given the scale of the epidemic and fear of the new virus, which many only fuels introduced worldwide the unprecedented restrictive measures in social networks and different kinds of pseudo-scientific sites immediately began to appear a variety of versions.

Someone seriously believes that invented 100 years ago, tuberculosis vaccines may at the same time to protect against coronavirus infection, the existence of which scientists didn’t know anything in December.

Others, however, argue that there was no connection and can not be: the coincidences are accidental, and immunity against coronavirus, which supposedly gives the vaccine and in which so many want to believe is fiction, no scientific evidence of this.

So what science says and what we know for sure?

Suspicious coincidence

Until about the middle of February, while practically not studied the disease raged only in China, it seemed that the new virus decimated indiscriminately broad scythe — the truth, often preferring men.

However, when the virus has reached the most remote corners of the planet, it became obvious that in different countries, the epidemic is evolving in different ways.

Somewhere in Italy or the United States — the number of confirmed cases of infection and deaths of patients soon began to grow by leaps and bounds. And somewhere- for example, in Japan or Thailand — the epidemic is spreading much slower, despite the fact that the first patients there revealed much earlier.

It is affected by many factors: the huge role played by the average age of the population, and cultural norms, the health care system, experience previously experienced epidemics, etc. in addition, the description of the course of epidemics in specific countries depends on how the testing how is statistics and information.

However, a number of scholars and analysts have suggested that there is another factor — the speed of development and severity of the epidemic in a particular country correlated with the fact whether there are children in the compulsory BCG.

This theory is mainly based on public statistics of infection by coronavirus. Engaged in the research, doctors say that the presence of BCG a particular person definitely does not give him immunity against the new virus. Vaccinated patients are among the seriously ill, and the death toll from Covid-19.

At the same time, it cannot be excluded that in the course of a pandemic vaccine may be useful at the national level: in any case, the preliminary data of this theory do not contradict.

The first relevant study on this subject was published in late March a group of scientists from new York. It has not yet been formally reviewed by other scientists working in this area, but the authors make a very bold statement.

“Our data suggests that BCG vaccination appears to significantly reduce mortality associated with Covid-19 — they write. We also found that the earlier a country began the practice of BCG vaccination, the greater the decrease in the number of deaths for every million residents.”

Epidemiologists from the University of Texas held a more large-scale study examining the statistics of 178 countries and came to the same conclusion. According to their calculations, the number of infected people per capita in countries with mandatory vaccination against tuberculosis below about ten times, and the victims Covid-19 — 20 times less than where BCG is no longer made.

What kind of vaccine so, what is special about it?

“Vaccination only”: the first attempt

Developed in France in 1921, BCG (from the French of Bacillus Calmette-Guérin — Bacillus Calmet-Guerin) and today remains the only available effective vaccine against tuberculosis recommended by who.

It works exactly the same as any other vaccine. A healthy person introduces a weakened pathogen to “get to know” the body with potential danger and formulate specific immunity.

Specific means is directed against a specific virus or bacteria that causes a particular disease. That is why immunizations are so many: for every disease — their own.

The BCG vaccine developed to protect against tuberculosis, and the idea of anything more she to protect cannot and should not.

However, a pair of scientists Peter Aaby and Christina Stabell Benn (both Danes, but work mostly in Guinea-Bissau) many years studying the side effects of the vaccination and claim that BCG provides effective protection from other diseases, strengthening the immune system as a whole.

According to their studies that have been conducted for several decades, people vaccinated with BCG become on average 30% less susceptible to all known infections, without exception. Whether it is a pathogenic virus, bacterium or fungus — without a difference: the probability of infection is reduced by almost a third.

However, all these years the scientific community treated the work of Aaby and Benn is pretty cool. They are published in scientific journals has been criticized for inaccuracies of the methodology, as conducted in 2014 a large-scale study who finally decided that if BCG has any additional benefits, they are so small that they do not take into account.

This history could be considered closed. But in 2020 came the coronavirus pandemic — and scientists noticed an unexpected numbers and strange correlations.

Italy, USA… who’s next?

There are not many countries where vaccination against tuberculosis has never been compulsory and universal. They can literally be counted on the fingers: Belgium, Italy, Canada, Lebanon, Netherlands, United States.

BCG write selectively to certain categories of the population and only in the recommended order.

Two countries from this long list are among the unfortunate leaders in the number of confirmed cases Covid-19. In the United States lives more than a quarter of all “officially infected” world. In Italy, whose population is five times smaller — one in ten.

Three more countries are not included in the top ten in absolute numbers, but are following each other immediately after it: Belgium is on the 11th place, the Netherlands — on the 12th, Canada 13th.

All three are way ahead of, say, Japan or Thailand, where the population is several times larger, and the first cases of the coronavirus have been recorded much earlier. If the 126 million people of Japan for the time of the epidemic from Covid-19 died less than 100 people, the 11 million people of Belgium to over 2000.

Institute for economic analysis based economist Andrei Illarionov, has studied the statistics of the dead and infected from 36 countries, where the “explosive” stage of the epidemic of the coronavirus began more than a month ago, and compared them with the carried out policy of vaccination.

Given the Institute’s calculations showed that in six “non-vaccinated” States the epidemic Covid-19 growing much faster than in countries where BCG mandatory put still. As the total number of infected persons per 1 million population, and the number of victims.

Countries where early vaccination did all the polls, but at some point stopped, the number of cases not inferior to the “unvaccinated”, but the proportion of fatal outcomes, there is less several times.

A similar analysis was conducted by the experts of the Institute of developmental biology (IDB RAS). There the country is divided not into three but into two categories: those where the mandatory BCG vaccination is not carried out at least 30 years (Belgium, Germany, Spain, Netherlands, Switzerland), and those where it is still included in the national calendar of vaccination in the EU (Bulgaria, Hungary, Latvia, Poland, Romania, Slovakia) and in other regions (Hong Kong, Indonesia, Kazakhstan, China, Mexico, Philippines, South Korea, Japan).

Unlike Illarionov, biologists deliberately not included in the list of the United States and Russia, where the epidemic started later, but otherwise the results of both studies were very close.

“In the second group the prevalence Covid-19 were significantly lower, which confirms the hypothesis of a possible produktivnosti BCG vaccine against Covid-19”, — stated in the letter that Russian scientists sent to the journal Lancet.

At the same time, the experts of the IDB emphasize: “the Differences between these groups of countries could potentially be due to other factors and only indirectly to be associated with BCG vaccination”.

Trap numbers

Is it possible that such an obvious connection, confirmed by several studies, is due to some other reasons?

Of course, statistics and knows many such examples. For example, the number of fire engines sent to the scene of the fire, is in direct proportion with the damage from fire, since both indicators depend first of all on the size of the fire. However, this does not mean that the damage can be reduced by sending less to the place of fire brigades.

Professor IBR ran Irina Lyadova gives two possible alternative explanations for the close ties between the BCG and the spread of coronavirus.

Firstly, compulsory BCG vaccination is carried out in the country with a relatively high incidence of tuberculosis. Many of them (although not all) — very poor state, and this can reduce the level and quality of testing and to create the appearance of a more prosperous situation Covid-19.

Second, the severity of the epidemic in different countries strongly influences the rate of adoption and the level of introduced quarantine measures.

“We cannot completely rule out the existence of a relationship between this indicator and policy on BCG vaccination, since both indicators depend on the historical peculiarities of the organization of epidemiological services and health systems,” she notes.

“Therefore, exclude the fact that in countries that use the BCG vaccine, which is more favourable for the epidemiological process is connected not directly with the protective effect of BCG, and other factors, not yet,” concludes Professor Lyadov.

“Trained immunity”

Is there any biologists in principle, any fundamental reason to assume that the TB vaccine might help with other viral infections?

Such grounds are, for the first time this mechanism has been described in an article published in the journal Science in 2016 the authors from the Netherlands have suggested that the memory of our immune system can be generated not only by mutation or recombination of any genes (so work shots), but without physical changes in the DNA.

The work of a group of scientists from the Netherlands so called “Trained immunity”, and about the BCG there was not a word. However, to test their theory the researchers decided with the help of this vaccine (and double blind testing).

In the end, they managed to prove that BCG can protect the body from infection, do not have tuberculosis nothing. At first it worked with yellow fever, and later with other viruses. Vaccinated infected control group less, and even picking up the infection, was sick not as hard and recovered faster.

But how about coronavirus? Does this mean that BCG and then may have the same effect?

All the experts emphasize that to say that the vaccine really does make people less susceptible to the virus SARS-CoV-2, can only be based on relevant clinical trials.

This is the only scientific way to test whether a correlation a causal relationship.

“Yes, this is only a correlation, but the hypothesis has a scientific basis — in the form of both recent and rather old studies published in serious journals — said Professor of the Department of immunology of the Moscow state University and corresponding member of the RAS Dmitry Kuprash. The doctors are right, that check the hypothesis”.

The tests are already running in several countries. In Australia, where BCG is not doing for almost 40 years, BCG planned to put 4000 young hospital staff.

Although Professor School of systems biology at the American University of George Manson Ancha Baranova questioned that the protective effect of BCG from a severe course of the disease, it will be possible to convincingly prove to the adults. There is considerable evidence to suggest that vaccination in childhood is more effective.

Pending the results

In the Russian scientific research Institute of vaccines and sera confirm evidence of the connection of BCG vaccination with reduced risk of various remembereing infections, allergies, cancer and overall mortality do exist.

“Such non-specific effects of BCG vaccination can be mediated by cells of the innate immune system and are not specific T-cell memory,” — explains the Director of the Institute, corresponding member of RAS Oxana Svitich.

If you do not go into the details, after inoculation of the cells of innate immunity for quite a long time left in an enabled state: they secrete substances that prevent inflammation, and gain the ability to “shift” the immune response, providing protection against any bacterial and viral infections.

In addition, the vaccine may stimulate a so-called heterologous immunity, and simultaneously activating specific T-lymphocytes to other antigens.

“Thus, BCG vaccination can not give specific protective immunity against coronavirus, but possible non-specific protective effect due to the activation of the innate immune system,” — said Svitich.

At the same time she believes that even in such a case “is unlikely to affect the spread of the epidemic in countries with different approaches to vaccination against TB”.

Like it or not, you can only say the results of retrospective studies, when the pandemic is over. Even the results of ongoing clinical trials will not until the end of December.

As reported ForumDaily:

  • A new virus was discovered in the Chinese city of Wuhan in December 2019. In 2020 it covers all continents except Antarctica. On 11 March, the President of the United States Donald trump has imposed a ban on entry into the United States from the EU. The ban came into force on Friday, March 13, and will last at least 30 days. In particular, it will affect people visiting the Schengen area for the last 14 days.
  • On 13 March, the tramp of coronavirus introduced in the U.S. nationwide state of emergency.
  • March 11, the who declared the situation with coronavirus pandemic, covering more than 110 countries. With symptoms COVID-19 caused by a coronavirus, can be found here.
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