Jabs to protect babies against potentially deadly winter virus pass final trials

Babies could soon be immunised against the potentially deadly and ubiquitous winter infection respiratory syncytial virus (RSV), and vaccines for pregnant women and older people are not far behind.

Australian researchers have completed final stage clinical trials of a long-lasting monoclonal antibody treatment called Nirsevimab, which works much like a vaccine, to protect infants from RSV infection.

A drug to protect infants from RSV is within reach thanks to a global effort spearheaded by Australian researchers.Credit:Shutterstock

Nirsevimab is expected to be submitted to regulatory bodies including Australia’s Therapeutic Goods Administration and the Australian Technical Advisory Group on Immunisation (ATAGI) for approval within 12 months.

It’s the first of nine experimental vaccines and prophylactic drugs emerging from the final stage of testing before they can be licensed for use and are the culmination of decades-long attempts to stop an infection responsible for 100,000 deaths and 3.6 million hospitalisations globally each year.

Roughly 6000 young children are admitted to hospital with RSV in Australia every year.

At the peak of RSV’s winter wave in June, more than 700 children a week were presenting to NSW hospitals with bronchiolitis – a condition caused by RSV where the tiny airways in the lungs become inflamed and fill with mucus, making it hard to breathe.

Respiratory syncytial virus is responsible for 100,000 deaths and 3.6 million hospitalisations globally each year.Credit:iStock

NSW has recorded 38,954 RSV cases and Victoria 17,741 this year.

Vaccines and monoclonal antibody treatments are designed to protect the body by mounting a defence against an invading virus. Vaccines work by mobilising the body’s immune system to produce infection-fighting immune cells that fight a virus, while monoclonal antibodies fight the virus directly.

Epidemiologists are already preparing for a national immunisation rollout by conducting a survey of pregnant women and parents of young children to gauge what they know about RSV and how they would feel about these vaccines and preventative drugs being given to newborns and in pregnancy.

Head of the Vaccine Trials Group at the Telethon Kids Institute in Perth, Professor Peter Richmond said: “As a paediatrician who has looked after sick babies with RSV for over 30 years, the idea that we could prevent a large proportion of these illnesses is fantastic, and I feel privileged to have been involved in the process.”

Professor Peter Richmond hopes in the next 10 years RSV vaccinations are available for all children, pregnant women and older people.

“I am very keen to make the most of this opportunity here in Australia,” he said.

The US and Europe are expected to license Nirsevimab for use by late 2022 or early 2023, the international network of scientists conducting clinical trials of the RSV revealed in The Lancet Infectious Diseases journal this week.

If Australian regulators follow suit – as they usually do – RSV immunisation could be available before the Australian winter – and RSV season – in 2024, Associate Professor Nicholas Wood paediatrician and sub-dean in the Discipline of Child and Adolescent Health at the University of Sydney said.

“Considering how bad [the] RSV season was this year, it will be very welcome,” he said.

Health Minister Mark Butler said it was great to see Australians again at the forefront of medical research, and it was up to the pharmaceutical company sponsors to provide a submission to the TGA, which along with ATAGI would determine whether it’s safe, effective and appropriate in an Australian context.

“An application to register it has not been submitted to the TGA at this stage,” Butler said.

Richmond said the burden “of disease we may be able to prevent will be even greater than first thought”, including reducing ear infections in babies and decreasing serious complications such as pneumonia associated with RSV. A further benefit would be in decreasing antibiotic prescriptions.

Among the candidates completing phase 3 trials are two vaccines for pregnant women that would enable antibodies to cross over the placenta to protect infants in the first six months of life, while clinical trial results for adults over 60 were also looking promising, The Lancet article reported.

Phase 3 trials of a second monoclonal antibody for premature babies and babies born with congenital heart disease or chronic lung disease began this week.

Richmond hoped that, in the next 10 years, vaccines and preventative drugs would be available for mothers, babies, toddlers and older adults, as well as combined COVID, influenza and RSV vaccines.

Professor Fiona Russell, paediatrician and specialist in infections, vaccines and global child health at the Murdoch Childrens Research Institute said safe and effective immunisations and preventative treatments for RSV could not come quickly enough.

“It’s long overdue,” she said. “This infection is what keeps children’s hospitals full each winter.”

A short-acting monoclonal antibody prophylactic has been available for high-risk infants for about 20 years, but the costly treatment involved monthly injections.

“The newer monoclonal antibodies are longer lasting and one injection given before the RSV season took off would last one season,” Russell said.

Associate Professor Hannah Moore at the Wesfarmers Centre for Vaccines and Infectious Diseases at Curtin University is part of the research team preparing for a future immunisation rollout by conducting a community survey about RSV awareness and vaccine acceptance.

“After many years working in this space, I can’t wait to see a safe and effective vaccine program for RSV implemented in our community, significantly reducing hospitalisations and longer-term effects of the virus,” she said.

The biggest challenge will be getting affordable RSV vaccines to poorer countries, that account for the vast majority of deaths and severe illness.

But no monoclonal antibody or vaccine is within reach for low-income countries that account for the vast majority of RV deaths and severe illness, the international group of researchers said.

Russell said, “It is critical that the development of vaccines have in mind how to make them accessible and affordable for children in the poorest countries, which account for 99 per cent of RSV cases.”

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