|The BCG or bacille Calmette-Guerin is a vaccine primarily used for tuberculosis disease. / Photo by Creativa Images via Shutterstock|
The BCG or bacille Calmette-Guerin is a vaccine primarily used for tuberculosis disease, a serious infection that affects the lungs and sometimes other parts of the body. The vaccine is used in many countries where TB rates are higher, according to the US Centers for Disease Control and Prevention.
Covid-19 mortality of BCG-using countries
A new study titled “Correlation between universal BCG vaccination policy and reduced morbidity and mortality for COVID-19” has found a correlation between nations that require BCG childhood vaccination and those with a smaller number of confirmed deaths from coronavirus disease. They found that countries with no universal policies on BCG vaccination are more severely affected compared to countries with long-standing and universal BCG policies. These countries with no policies of BCG vaccination include the USA, Netherlands, and Italy.
Gonzalo H. Otazu from the New York Institute of Technology is the lead author of the study. He started working on the analysis after he observed a low number of Covid-19 cases in Japan. Although Japan reported some of the earliest confirmed cases of coronavirus outside China, it still had not implemented a lockdown like other countries.
In another recent study by Anita Shet from the Johns Hopkins Bloomberg School of Public Health and colleagues, it also notes that the Covid-19 mortality of BCG-using countries was 5.8% lower compared to non-BGC-using countries. These two studies appeared in a pre-print server for health sciences medRxiv.
Eleanor Fish, a professor at the immunology department of the University of Toronto, urged caution should still be observed as the Otazu’s study has not undergone review by peers, which is a strict criterion observed in science studies. Professor Fish is not involved in the two studies mentioned. She said that she will be reading the result of the study with “incredible caution.”
|The vaccine that was developed a hundred years ago to fight TB is also being tested against Covid-19. / Photo by MAMIAE T8 via Shutterstock|
The 100-year-old vaccine
The vaccine that was developed a hundred years ago to fight TB is also being tested against Covid-19. BCG is known to “train” the body’s immune system to recognize and respond to various infections, including parasites, bacteria, and viruses, the experts said. Although there is little evidence that BCG can blunt coronavirus infection, the results of a series of clinical trials may answer this question a few months from now.
In Melbourne, Australia, for instance, scientists have started administering the vaccine and a placebo to thousands of respiratory therapists, nurses, physicians, and other healthcare workers. This is the first randomized controlled trial meant to test the effectiveness of the vaccine against Covid-19. Melbourne-based Royal Children’s Hospital’s head of infectious diseases Dr. Nigel Curtis said no one is considering it as the solution to the Covid-19 but that they want to reduce the time that infected healthcare workers are sick so they can quickly recover and come back to work faster.
A few days ago, the Netherlands also conducted a clinical trial of 1,000 healthcare workers. Nijmegen-based Radboud University Medical Center’s infectious disease specialist Dr. Mihai Netea shared that 800 healthcare workers have signed up for the trial.
Massachusetts General Hospital’s director of immunobiology Dr. Denise Faustman is also looking for funding to begin a clinical trial for their healthcare workers in Boston and the preliminary results will be released in four months. Dr. Faustman said that there is already strong data from clinical trials with humans that the BCG vaccine protects people from parasitic and viral infections.
As for the correlation between the TB vaccine and Covid-19 mortality, Trinity College Dublin professor of biochemistry Luke O’Neill shared via Irish Times that it is the “most significant development” since Covid-19 has spread. He stressed that although the study is a statistical one and comes with limitations, it is feasible. It does not mean that people should change their behavior, such as washing their hands and physical distancing. It’s just that it “should be considered.”
However, government agency Health and Safety Executive has confirmed that Ireland has had no BCG vaccine since 2015. This means that no children had been vaccinated with BCG since then. This also coincided with a vaccine shortage in Europe.
Coverage of BCG vaccine
Nearly 4 billion people in the world have been vaccinated with BCG. Countries with the highest share of one-year-olds vaccinated against tuberculosis (BCG) in the recent data provided by scientific online publication Our World in Data are Russia (96%), China (99%), Turkmenistan (99%), Saudi Arabia (98%), Egypt (96%), Libya (99%), Algeria (99%), Morocco (99%), Brazil (99%), Bolivia (99%), Argentina (99%), Mexico (96%), Botswana (98%), Malaysia (99%), and Thailand (99%), among others.
Nations with the lowest share of one-year-olds vaccinated against TB are Somalia (39%), Ukraine (39%), Sweden (24%), and Portugal (32%).
In 2018, 89% of children globally received the tuberculosis vaccine, 86% of children were vaccinated by 1st dose of measles, 86% diphtheria/tetanus/pertussis, and 85% polio.
Covid-19: vaccine development effort
The World Health Organization reports that there are more than 50 vaccine candidates for Covid-19 and two are in clinical trials. As part of the vaccine development effort, pharmaceutical companies, multiple governments, and philanthropists have contributed hundreds of millions.
Vaccines serve two distinct functions. One is they protect the vaccinated individual against infection and second, they reduce transmission thus protecting people who are not vaccinated. It drastically reduces the spread of the virus.
Confirmed Covid-19 deaths, by country or territory
Meanwhile, countries with the highest recorded number of deaths due to coronavirus are Italy (17,669), USA (14,797), Spain (14,792), France (10,869), UK (7,097), Iran (3,993), China (3,335), Belgium (2,523), Germany (2,349), and the Netherlands (2,248). In epidemiology, the death rate is calculated by dividing the number of deaths to the number of people in the population and then multiplying it by 100, 1,000, or another convenient figure.
The world is struggling to control the spread of the virus. Experts believe that it may take a year for a vaccine specifically meant for Covid-19 to be available for the public and if a drug is discovered, it may also take a few months to determine its effectiveness. This is why scientists are considering the tuberculosis vaccine as a potential game-changer in the world’s fight against Covid-19.