Can the new wave of RSV vaccines stop the dangerous virus?

Last week, drug company Moderna announced promising results from a clinical trial of a vaccine against the potentially fatal disease respiratory syncytial virus (RSV) in people over 60. Pharmaceutical companies Pfizer and his GSK announced similar Phase III results for this age group last year. Both are currently pending regulatory approval. Pfizer also applied for approval to administer the vaccine during pregnancy and received results showing it protected the newborn from her RSV. Assuming they are approved soon, what might the impact of these first her RSV vaccines be?

RSV usually causes mild cold-like symptoms, but can be dangerous in very young and older people.in the case surge in recent monthsis stressing the health care system. For babies from about one month to he one year old, RSV is her second leading cause of death in the world after malaria.For adults, data are sparse: study¹ in 2022 RSV kills 6,500 people in the US each yearwith the highest percentage of people over the age of 65.

However, products being developed for each age group present different opportunities and challenges. “The RSV vaccine field is not one he is, but two,” says Louis Bont, a pediatrician who specializes in infectious diseases at the Utrecht University Medical Center in the Netherlands. “One is to protect the baby, the other is to protect the elderly.”

The quest for an RSV vaccine began in the 1960s, notable failures along the way. Ah Breakthrough in 2013² of Deciphering protein structures This virus, which the virus uses to colonize and enter human cells, paved the way for the current wave of RSV vaccines.

stable protein

Moderna’s mRNA-based vaccine stimulates the production of a stabilized version of this protein, while Pfizer and GSK’s vaccines directly inject a synthetic version of this protein. While their efficacy has been very similar in trials, Bont expects to see differences in the initial protection they provide and the persistence of immunity after larger deployments.

An RSV vaccine for people over 60 is the closest available. However, even if approved, it is not clear what the uptake in this age group would be.

Early COVID-19 vaccination coverage was high among older adults, but “it was a pandemic emergency,” said Christine Shaw, vice president and portfolio head of respiratory vaccines at Moderna in Cambridge, Massachusetts. increase. For RSV, “awareness and fear are not the same”. COVID-19 booster intake is declining in older populations, and flu jabs may not be as popular as public health experts would like. Shaw said Moderna is looking at whether it can combine the RSV vaccine with COVID-19 boosters and/or flu shots for greater convenience.

It is also not clear how strongly countries will recommend vaccination for people over 60. In South Africa, for example, the impact of his RSV vaccine on older adults is likely to be relatively low, said Cheryl Cohen, an epidemiologist and respiratory disease expert at the University of the Witwatersrand in Johannesburg, South Africa. I’m here. Elderly people represent a small proportion of the total population and influenza vaccination is under-represented in this group.

Benefits for your baby

When it comes to infant vaccines, Cohen says, it’s a different story. “This is one of the top new products we look for. The fact of being in contact – the fact that the vaccine can be integrated into routine care – applies to all low-, moderate-, and high-income countries.

“I think in 10 years we’ll be talking about RSV vaccines in mothers, and we’ll look back and say, ‘Look at what this moment in public health history was,'” says Alejandra Gurtman. . , Vice President, Vaccine Clinical Research and Development at Pfizer, New York City.

Vaccination during pregnancy produces high levels of maternal antibodies that pass through the placenta to the fetus and protect the baby during the first few months, explains Gurtman. A trial showed that babies born to people who were vaccinated during pregnancy were significantly less likely to develop RSV infection requiring clinical intervention. It says it plans to, but GSK canceled the pregnancy trial last year over safety concerns.

The optimism for RSV prevention in children extends beyond vaccination of pregnant women. Another method is to prophylactically inject the newborn with an antibody against the RSV protein. One such antibody, developed by AstraZeneca and Sanofi, was approved for widespread use in November 2022. In addition to giving parents a choice, antibodies may be important for premature babies, says Bont. Babies who have not received sufficient antibodies from their vaccinated parents.

The Bill & Melinda Gates Foundation and the Vaccine Alliance, Gavi, are working to improve access to RSV vaccines and monoclonal antibodies in low- and middle-income countries. However, Bont and Cohen stress that continued advocacy and political prioritization will be required to ensure equitable access.