Hyderabad: India may have a ray of hope in its battle against global coronavirus pandemic because of the universal BCG vaccination policy adopted by the country to prevent the spread of Tuberculosis (TB).
BCG vaccination can be a non-specific stimulator of immunity but it cannot be said at this stage whether it will work in our favor or not, observed public health expert Dr K Srinath Reddy while reacting to a study that found universal BCG vaccination helpful in reducing the mortality and spread of COVID-19 in a country.
A study by the New York Institute of Technology (NYIT) found that countries without universal BCG vaccination such as USA, Italy and Nederland have been severely affected by COVID-19 virus in comparison with those countries that have long-term universal BCG vaccination.
The authors of the study, which is a pre-print and yet to be reviewed by peers, ignited a debate among the medical community about its potential use in the fight against novel coronavirus. Some countries, including Germany, are soon going to start the trial of this 100 years old Bacillus Calmette-Guerin (BCG) vaccine to protect their health workers who are at the frontline of global war against SARS-CoV-2 virus.
BCG vaccine, which was developed by French biologists Albert Calmette and Camille Guerin in the early 20th century, contains weakened Mycobacterium bovis bacteria that affects cattle but is related to Mycobacterium tuberculosis bacteria which causes TB in humans.
The study titled ‘Correlation between universal BCG vaccination policy and reduced morbidity and mortality for COVID-19: an epidemiological study’, analysed several aspects of COVID-19 outbreak such as the starting year for universal BCG vaccination in a country, its phasing out and interruptions, impact of COVID-19 in late starters like Iran and the lethality of the virus in other countries such as the USA, Italy and Nederland that never had an universal BCG vaccination policy.
The study found that 55 middle and high income countries with current universal BCG policy reported a lower mortality rate per million people. In contrast, five countries with similar income had a high mortality rate.
“We also found that BCG vaccination also reduced the number of reported COVID-19 cases in a country. The combination of reduced morbidity and mortality makes BCG vaccination a potential new tool in the fight against COVID-19,” concluded the authors of the study.
The authors did not include India despite its long standing universal BCG vaccination policy as they linked low level of reported COVID-19 cases in the country to low level of testing.
However, inclusion of Japan in the study that started BCG vaccination in 1947, around the same time as India, which started it a year later in 1948, does provide a ray of hope for the country if the findings of NYIT University are further corroborated by studies that have been planned in other countries including Germany and Australia.
In the study the authors pointed out that despite strong curtailing of social interactions in Italy, which never had universal BCG vaccination, the mortality was still very high.
"In contrast, Japan had some of the earlier cases, but the mortality is low despite not having adopted some of the more restrictive social isolation measurements,” noted the study.
According to Johns Hopkins University’s Corona Resource Centre, Italy reported the maximum number of deaths, over 15,887 deaths and third highest confirmed cases in the world, over 1,28,948 cases as on Monday.
In contrast, Japan, which started universal BCG vaccination since 1947, reported just 85 deaths and 3,654 cases despite reporting some of the first corona cases outside of China.
India reported 109 deaths and 3,666 active cases as on Monday (12.30 pm IST).
Anti-bacterial vaccine helpful in boosting anti-viral immunity
Although, BCG vaccine has been used to induce immunity against bacterial infection, particularly against TB bacteria, but it is reported to have some positive side effects as well as it also helps in boosting the anti-viral immunity in humans.
"BCG vaccination significantly increases the secretion of pro-inflammatory cytokines, specifically IL-1B, which has been shown to play a vital role in antiviral immunity,” noted the authors while quoting another study on the positive impact of BCG vaccine.
India’s long running BCG Vaccination Programme
According to BCG Atlas, India started BCG vaccination as a pilot project in 1948, followed with the immunisation programmes in school a year later. The country went for a mass immunisation programme during 1951-59 period.
In 1978, India extended BCG vaccination at birth or within one month of the birth of a child and the coverage of BCG vaccination has been made universal since 1985.
However, the elderly population of the country, which is most vulnerable to COVID-19, had been left out of the BCG coverage due to its late start in comparison with other vaccines such as the vaccination programme against smallpox.
History of vaccination in India started as early as 1802 when a 3 year old child in Bombay received the first smallpox vaccine in the country in June 1802. However, it was limited to smallpox vaccination thought the trials were also conducted for plague and typhoid vaccines. The national tuberculosis programme using BCG vaccination was launched in 1962.
However, except elderly population, the majority of Indians born after 1962 are likely to have received the BCG vaccine. According to the BCG World Atlas, India has 99% coverage of BCG vaccination.
Can Japan’s example be applied on India
Authors of the study have noted that COVID-19 has affected different countries differently but there could be several reasons for that such as level of testing, quality of the health care facilities available in a country and the containment measures adopted by a country among other things.
For example, one of the reasons for Japan’s success against COVID was attributed to the fact that it has higher level of hand washing in comparison with other developed countries and less common handshakes and hugging due to cultural reasons. Japan is also known for its cleanliness and hygiene and a well-trained population to deal with such kind of global pandemics.
While commenting on the findings of the NYIT study that linked the less severe impact of COVID-19 on a country with the presence of a long-term BCG vaccination policy, Dr Reddy said: “There is some correlation in that sense, but correlation is not causation. We will have to wait for more evidence to come in.
Dr Reddy said some other countries like Australia, Germany and others have started trials of BCG or its variants and it will provide more information to Indian authorities.
“This will also give us some information about what is the degree of protection and whether it (BCG Vaccine) is indeed protective or partially protective,” Dr. Reddy told ETV Bharat.
“These are all rays of hope but I am not going to say that this is a definite basis for our future expectations and models, we will have to wait and see,” added Dr. Reddy.
