Improved COVID outcomes in nations with higher TB vaccine

Researchers have found that tuberculosis (TB) vaccine administered during the past 15 years is associated with significantly improved Covid-19 outcomes.

For the study, published in the journal 'Vaccines', researchers from the Ben-Gurion University of the Negev and Hebrew University of Jerusalem in Israel, wanted to analyse the correlation between the Bacille Calmette-Guerin (BCG) vaccine for tuberculosis and Covid-19 outcomes.

The researchers discovered that BCG regimes are associated with better Covid-19 outcomes, both in reducing infection rates and death rates per million, especially for ages 24 or younger who had received the vaccination in the last 15 years.

"Our findings suggest exploring BCG vaccine protocols in the context of the current pandemic could be worthwhile," said study researcher Nadav Rappoport of the Ben-Gurion University.

"A growing number of clinical trials for testing the efficacy of BCG vaccination have been initiated," Rappoport added,according to the research team, there was no effect among older adults who had received the BCG vaccine.

Many countries have stopped inoculating their entire population, but some still use BCG widely. The researchers analysed data from 55 countries with populations of more than three million people, which comprise some 63 per cent of the world's population.

As the pandemic reached different countries at different dates, they aligned countries by the first date at which the country reached a death rate of 0.5 deaths per million or higher. They controlled for 23 variables including demographic, economic, pandemic-restriction-related, and country health-based.

BCG vaccine administration was shown to be constantly associated with Covid-19 outcomes across the 55 countries. To ascertain whether other vaccines also influenced Covid-19 outcomes, they conducted the same analysis for the measles and rubella vaccines and found that those did not have a significant association with Covid-19 outcomes.Other epidemiological studies have shown the effect of the BCG vaccine beyond tuberculosis, but scientists do not yet know why the vaccine has such an effect.

Recently, a study published earlier this month in the journal 'Cell Reports Medicine', revealed that the BCG vaccine has a general stimulating effect on the immune system and is therefore effective against Covid-19.