Vaccination against RSV infections in the starting blocks

RSV infections have also led to a large number of illnesses and hospitalizations in Austria in recent weeks and months. Many of those affected survive such infections without major problems, but they are not harmless. RSV causes approximately 60,000 deaths in hospitalized children under five years of age worldwide each year. The second “spike” in terms of disease rates is in seniors: About 14,000 people over 65 die from RSV infections each year in the US alone, and 177,000 are hospitalized. About 33,000 elderly deaths and almost 500,000 hospitalizations are expected in Western industrialized countries.

Vaccine for seniors at your fingertips
That is why vaccines have been researched for years. This may have only been successful in the recent past. For example, the British pharmaceutical company GlaxoSmithKline (GSK) has developed a vaccine for seniors that is currently being examined for approval by the European Medicines Agency (EMA). In the US, the decision on possible market approval is already pending May next year.

Vaccine worked
The efficacy trial (Phase III) containing data relevant to Glaxo vaccine approval was published late last week in the New England Journal of Medicine. Veronica Hulstrom of the British pharmaceutical company and her co-authors tested the effectiveness and tolerability of the RSVPreF3 OA vaccine candidate in their study (DOI: 10.1056/NEJMoa2209604) with 24,966 subjects over 60 years of age. Half of the participants received one dose of the vaccine. The antigen is the so-called F protein of the RSV pathogen in a special three-dimensional shape. There is also an adjuvant booster.

In the group of 12,466 people who received the vaccine, there were seven infections. 40 infections were registered in the placebo group of 12,494 people. That was an almost 83 percent reduction in the infection rate. The protection rate against serious RSV diseases, which often lead to hospitalizations for lung problems, was even higher: about 94 percent. There were no serious complications that could be related to the vaccination. The main adverse reactions were injection site pain, headache and transient fatigue.

“A single dose of RSVPreF3 OA vaccine had an acceptable safety profile and prevented RSV infection, lower respiratory tract disease, and serious RSV-related disease in adults over 60 years of age, regardless of virus subtype (RSV A and RSV B; NB) and of comorbidities,” the researchers wrote.

Successes for other candidate vaccines
The pharmaceutical company Janssen-Cilag (Johnson & Johnson) is also active in this area. A phase II study (DOI: 10.1056/NEJMoa2207566) of an adenovirus-based vector vaccine containing the RSV F protein mRNA is also published in the current New England Journal of Medicine. The study included 5782 subjects over the age of 65. Overall, depending on the different disease categories, the effectiveness in preventing RSV disease was between 70 and 80 percent compared to placebo. An even larger phase III efficacy study will follow.

Protection of babies by vaccination of pregnant women
Although these two studies concerned the protection of the elderly, the US pharmaceutical company Pfizer apparently successfully pursues the concept of protecting newborns and babies by vaccinating pregnant women. The group only published the first data on the effectiveness of its vaccine candidate against RSV late last year.

“The efficacy of the vaccine in preventing severe RSV disease requiring medical intervention in newborns within the first three months of life was 81.8 percent. In the first six months of life this was 69.4 percent. The RSVpreF vaccine candidate was well tolerated. There were no concerns about the safety of the vaccinees or their babies.”

About 7,400 pregnant women in 18 countries were randomly vaccinated with 120 micrograms of the vaccine or a placebo. This happened in the late second or third trimester of pregnancy. The antibodies that were passed from the expectant mother to the unborn child apparently offered good protection. Pfizer also wants to market the vaccine for the elderly.