Respiratory syncytial virus and the race for a vaccine

Respiratory syncytial virus (RSV) usually causes mild, cold-like symptoms. It is a very common illness in all age groups, however, it can be more serious in people over 65, people with underlying health conditions and in infants, sometimes causing severe bronchiolitis and even death.

While cases of RSV typically rise during the flu season, infections started increasing earlier than usual this year, with more young children requiring hospitalization than in previous years.

According to a new study published in The Lancet, one in 56 otherwise healthy babies is being hospitalized in Europe due to RSV.

One possible reason for the surge in infections is the lockdowns of the last two years. The lack of exposure to common viruses could mean that people’s immune systems are not as well-prepared to fight infection as they might have been previously.

RSV vaccines in the pipeline

Scientists began researching a vaccine candidate for RSV as far back as the 1960s, however the first vaccine triggered serious illness and in the case of two infants, death. This deterred further research until more recently, when scientists had acquired a greater understanding of RSV. 

Now governments and public health experts are sounding the alarm over the potential “tripledemic” of Covid-19, influenza and RSV. As a result, a number of vaccine manufacturers are at various stages of development and approval of an effective vaccine for the respiratory disease.

GSK has developed a vaccine for adults aged 60 and over that has had positive results in clinical trials. As the first RSV immunization aimed at this age group, it has so far been approved for use in Japan, with separate decisions for the US and EU markets expected by the end of the year.

Bavarian Nordic A/S, Johnson & Johnson, Merck & Co and Moderna are also developing vaccines, with the latter courting controversy for promoting its three-in-one vaccine targeting Covid-19, influenza and RSV before completing Phase III clinical trials.

An effective vaccine for infants and babies

Unlike the Covid-19 immunizations aimed at vaccinating entire populations, pharma companies are targeting specific demographics to prevent RSV. For instance, Pfizer has produced a vaccine to be administered during the second or third trimesters of pregnancy, so that antibodies are transferred through the placenta to the fetus.

Clinical trials have found it is 82 percent effective at preventing severe RSV in babies under three months old, and Pfizer is preparing to apply for approval from the US Food and Drug Administration (FDA) before the end of the year.

Two vaccines have already received approval for use in Europe.  The joint vaccine from Sanofi and AstraZeneca is a single-dose immunization for newborns and infants. The monoclonal antibody drug is being sold under the brand name Beyfortus. The other is palivizumab, marketed as Synagis by Orphan Biovitrum. 

Quick links

• Top 10 vaccine manufacturers worldwide
• Tackling infectious disease with innovative R&D approaches
• Bivalent Covid-19 vaccines: What they are and what they do

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