A team of scientists from India has just verified that an ancient tuberculosis vaccine can help the elderly to protect themselves from COVID-19.
In countries like Spain, where the 100% of the population over 80 years of age and to a very high percentage of those over 60, it may seem unnecessary to us. However, there are many countries in the world where coronavirus vaccines they have barely made an appearance. Therefore, while the elderly wait their turn, it does not hurt to look for ways to keep them minimally protected.
In this case, it could contribute to reduce symptoms of COVID-19 in case they become infected. And, with it, avoid hospitalizations and deaths. For now, as explained by the results of the study that have just been published in Science Advances, the results of the first clinical trials have been very positive.
Why the tuberculosis vaccine and not another?
The Bacillus Calmette-Guérin (BCG) is an old tuberculosis vaccine based on the use of live attenuated pathogen.
It has certain parallels with the first vaccine in history, the one that Edward jenner developed to combat smallpox. And, instead of using the bacteria that generally cause disease in humans, a strain of the bacteria that causes tuberculosis in cows is used: Mycobacterium bovis. Jenner also used a bovine variant of smallpox, although she did not alleviate it. Therefore, BCG, although in disuse, is much safer.
During the years that its use was widespread, it was seen that this tuberculosis vaccine was not effective only against that disease. It also seemed to protect the vaccinated from other respiratory conditions. The reason, these scientists explain, is that, apart from the specific response, it also seems to generate a nonspecific immunity.
Therefore, this group of researchers, from the National Institute of Tuberculosis Research and the National Institute of Epidemiology of India, decided to see if it could also be useful against COVID-19. Although there was something very important that they had to analyze before: does the vaccine generate a inflammatory answer excessive?
Interim protection against COVID-19
When a pathogen enters our body, the entire defensive battalion of the immune system confronts it. This is a beneficial thing, of course. The problem is that defensive response It also affects us, through the inflammation. Continuing with the warlike simile, it would be the result of a large esplanade trampled by horses and covered by the bodies of the soldiers who perish in battle. If this occurs in its proper measure, it does not have to be dangerous. After all, it is necessary. But sometimes it happens in an excessive way, endangering the life of the patient.
In the case of elderly, as they get older, they are developing a chronic low-grade inflammation. If it joins the immune response itself, it can be dangerous. That is precisely why it is believed that they constitute the population group more susceptible to severe COVID-19.
And, of course, vaccines also generate an inflammatory response. It is the reason why many of us have experienced symptoms such as fever, headache or inflammation in the arm from the puncture with them. Apparently, BCG could protect the elderly from COVID-19 thanks to its nonspecific immunity. But at what cost?
With this in mind, the authors of this study recruited 82 volunteers aged between between 60 and 80 years. Half were given the tuberculosis vaccine, while the other half were injected with a placebo.
Then a month was allowed to pass, after which blood samples were collected from all of them. The objective was to analyze the levels of certain components of the immune system related to inflammation. Specifically, they focused on interleukin 6, interleukin 2, type 1 interferons, tumor necrosis factor alpha, and granulocyte and macrophage colony stimulating factor. They found that, although they were in both groups, the levels were much lower in those who had received the tuberculosis vaccine rather than the placebo.
Many of these components are known to be related to severe symptoms of COVID-19. Therefore, the study authors believe that this vaccine could give some protection to the elderly who are still waiting to receive one of the coronavirus vaccines. It is essential that they receive them as soon as possible. In fact, the WHO has already asked rich countries to donate their surpluses instead of opting for a third dose that does not even seem to be necessary at the moment. However, while they wait, any help is welcome. It would be more.