Babies whose mothers were vaccinated against respiratory syncytial virus had less need for drugs against bacterial infections
14 March 2022
A vaccine against a virus that causes chest infections in young babies has an unexpected effect – it cuts the number of antibiotics given to treat bacterial infections.
The results, from a large trial of a vaccine against respiratory syncytial virus (RSV), suggest the jab could help reduce antibiotic resistance, says Joseph Lewnard at the University of California, Berkeley.
RSV is a common cause of colds in children. Some who catch it when very young develop severe chest infections, so several firms are working on vaccines, given either to babies or pregnant people. The latter works because antibodies cross the placenta to reach the fetus in the uterus.
Resvax is an experimental vaccine designed for use in pregnancy developed by US biotech firm Novavax. In 2019, the company reported results from a large randomised trial that found it reduced RSV infections in babies, but not by enough to meet its objectives.
But Lewnard’s team wondered if the trial would show any effects on antibiotic use. These medicines don’t work against viruses – they only treat bacterial infections – but doctors may prescribe them if they don’t know the cause of an infection. Also, RSV can sometimes lead to secondary infections by bacteria.
The trial recruited about 4500 pregnant women in 11 countries and gave two-thirds of them the RSV vaccine, while the rest got a placebo injection. Babies whose mothers got the RSV jab received 13 per cent less antibiotics in their first three months of life, mainly for pneumonia and other lower respiratory tract infections.
This suggests that if any of the other RSV vaccines in development reach the clinic, they may cut antibiotic use and so reduce antibiotic resistance, says Lewnard. “There’s plenty of data to show that we have too much antibiotic resistance in the world,” he says. “Antibiotic resistance is a growing problem in terms of the burden of disease and death.”
Journal reference: PNAS, DOI: 10.1073/pnas.2112410119
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