Respiratory syncytial virus (RSV) usually causes mild cold-like symptoms but can be severe in vulnerable people CDC/Science Photo Library/Alamy
Respiratory syncytial virus, better known as RSV, kills the very young and the very old, but we can almost certainly hope it never becomes so deadly. We are at a turning point in the fight to prevent.
On January 17, Moderna reported promising results from a vaccine trial in the elderly. This is the latest of four trials by various pharmaceutical companies that have released very encouraging results, as 2023 will be the first year in the world that his RSV vaccine will be approved. It may mean that
Additionally, a long-lasting antibody treatment that prevents otherwise healthy babies from contracting RSV has been approved in the European Union and the United Kingdom in 2022. If these precautions work as promised, together they can save tens of thousands of lives.
RSV infects us all in our lives. It causes flu-like symptoms in most people, but can be fatal among the more vulnerable, such as babies and the elderly.
About 100,000 children die from RSV each year worldwide, most of them very young, says Harish Nair of the University of Edinburgh, UK. Of those deaths, 97% occur in low- and middle-income countries, he says.
As for mortality rates among the elderly, we don’t know the exact numbers, says Nair. At least 15,000 adult RSV deaths are reported annually in high-income countries, and the risk increases with age. But most people aren’t tested for the virus, so the real numbers are probably two to three times higher for him, he says. There are no statistics on his RSV deaths among older people in low- and middle-income countries.
For every RSV death, more people become seriously ill and millions require hospitalization.
Developing an RSV vaccine has historically been difficult because the main protein on the outside of the virus, called the F protein, changes shape when it infects a cell. We target the part of this protein that is exposed only before the shape change.
In 2013, researchers at the US National Institutes of Health published a synthetic version of the F protein that locks into its pre-infectious shape. Companies like GSK, Pfizer and Moderna have developed vaccines based on this locked open protein.
While the GSK and Pfizer vaccines consist of the protein itself, Moderna’s vaccine contains the mRNA sequence that encodes it, allowing cells to make the protein after injection.
In trials in people over the age of 60, each vaccine was more than 80% effective in preventing symptomatic infections.
This suggests that regular provision of one of these RSV vaccines to people over the age of 60 could save many lives, but Nair said the deployment would only be available in high-income countries. expected to be done. She recognizes the toll of RSV and the need for a vaccine.
Because trials are still in their early stages, it is not yet known how effective the RSV vaccine will be in young children. However, in November 2022, Pfizer found that if the vaccine was given during pregnancy, it was about 80% effective in preventing severe infections in infants up to 90 days of age, after which this protection was waning. reported that
Early protection is a result of antibodies acquired by the baby through the placenta and circulating in the blood.
Similar protection can be provided by injecting factory-made antibodies. In 2022, the EU and UK approved an antibody called nirsevimab (Beyfortus). This is after studies showed that getting him one injection before her RSV season protected the baby from severe infections. This antibody is being evaluated for approval in the United States.
Nirsevimab is not the first antibody to prevent RSV infection, but it lasts longer in the body, allowing it to be given to healthy babies as a preventive measure. But its manufacturer, AstraZeneca, has yet to announce pricing for the antibody, Nair said. Factory-made antibodies tend to be very expensive.
However, with Pfizer’s vaccine expected to be approved for use during pregnancy in many countries, there are now two options for preventing RSV infection in babies: antibodies and a vaccine given during pregnancy. There is a possibility that some countries will soon have it. Given that half of her RSV deaths in children are in infants under 6 months of age, infant mortality could be significantly reduced.
Therefore, there are many reasons for optimism that the number of deaths and medical complications from RSV will decrease significantly.
“New products are coming,” says Nair. “New technology is coming. It looks very, very promising.”
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