TB vaccine could protect babies against new infectious diseases

TB vaccine could protect babies against new infectious diseases
© iStock-Manjurul

A new study has shown that a tuberculosis (TB) vaccine could help to protect newborn babies against a number of different infectious diseases – potentially including COVID-19.

The randomised control study was led by the London School of Hygiene & Tropical Medicine (LSHTM) through the MRC/UVRI & LSHTM Uganda Research Unit, and funded by the Wellcome Trust. It studied the tuberculosis (TB) vaccine Bacillus Calmette-Guerin (BCG) and involved  560 newborns in Uganda, who were monitored for a range of illnesses. It found that infection rates from any disease were 25% lower in the group who received the vaccine at birth, compared to the group that had not yet received the vaccination.

This is the first research to rigorously investigate the full range of illnesses BCG could protect infants against.

Vaccines on the day of birth

In the study, healthy Ugandan infants were randomly assigned to receive the BCG vaccine either at birth or at six weeks of age, and were then followed-up by doctors, blinded to the intervention, for 10 weeks to look for episodes of any type of illness or infection. The two groups presented to doctors with infections of any kind, except TB, were compared to see whether having BCG made a difference. They also took blood samples from both groups, to look at differences in their innate immune system, the body’s first line of defence against infections.

The researchers found that  infants who had been vaccinated with BCG at birth presented to doctors with any kind of infection 25% less often than infants who had not.

The authors have suggested that vaccinating all babies on the day they are born with the BCG vaccine could help to reduce neonatal infection and death in areas with high infectious disease rates, and that results from the study show a possibility that the vaccine might be used to protect children and adults against COVID-19 and other new infectious diseases.

The study found that vulnerable groups such as low birth weight babies, and boys, seemed to gain the most protection from the vaccine, and that it appeared to protect against mild, moderate, and severe types of infections.

Sarah Prentice, lead author from LSHTM, said: “Nearly a million babies die every year of common infections, so we urgently need better ways to protect them. Our research suggests that ensuring that BCG is given at birth could make a big difference in low-income countries, potentially saving many lives.”

Hazel Dockrell, Professor of Immunology at LSHTM and one of the co-authors of the study, adds: “It’s very exciting to think that BCG vaccination might help keep newborns safe against other dangerous infections, in addition to providing protection against TB. Although BCG is recommended at birth in many countries, it is often delayed due to logistical difficulties. Ensuring that the vaccine is given on day one, in areas with high rates of infectious disease, could have a major impact on infections and deaths in the newborn period.”

Protection against novel viruses

The team are unable to definitively say why BCG offered additional, non-specific protection, but highlight that the research showed evidence of changes in the innate immune system of vaccinated infants, leading the researchers to suggest that it could provide protection in the early stages of novel outbreaks, such as COVID-19 or Ebola.

Further studies are already underway to explore whether BCG could play a role in the response to COVID-19, with large trials involving healthcare workers and the elderly.

Dr Prentice said “Since the findings show that BCG seems to offer wider protection against a range of infections, our study also raises hopes it might be useful in protecting the general population against COVID-19 and future pandemics – though we will need to see the results of other, more specific studies to know for sure.”

The researchers note that it is worth investigating whether reintroduction of BCG in countries where it is no longer in routine use, such as the UK, is beneficial at protecting vulnerable infants in neonatal units against other infections.

The authors acknowledge limitations of their study, such as that it was relatively small and it was not possible to show an effect of BCG on numbers of deaths from infections in the study participants.

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