Pharmaceutical company Pfizer has started production of its respiratory syncytial virus (RSV) vaccine with the prospect that it will be licensed in the European Union and the United States in the fall after its efficacy and safety have been demonstrated in clinical trials.
Although most RSV infections are mild and limited to cold symptoms, they can cause serious complications in young children and older people. There is still no approved vaccine in the world to prevent infection.
The product is inoculated into mothers during pregnancy so that the antibodies reach the fetus through the placenta
In the pediatric population, RSV can cause bronchiolitis, an inflammation of the smallest respiratory ducts, and this past autumn it has filled pediatric ICUs in Spain. Three million children under five years of age are hospitalized each year worldwide due to RSV and more than 100,000 die, most under six months of age.
In older people, it causes more than 150,000 hospitalizations a year in Europe.
“We hope to have the vaccine available for the next RSV season (…). We have applied for approval in the United States and in Europe,” Kena Swanson, vice president of Vaccine R&D at Pfizer, said Thursday in a meeting with journalists at the company’s factory in Puurs, Belgium.
The approval of the first effective and safe vaccine against RSV will be a historic milestone. It was a long-awaited vaccine.”
In a clinical trial with 7,392 participants from seven countries, the vaccine has reduced severe respiratory infections due to RSV by 82% in the first three months of life and by 69% in the first six months. The vaccine has been administered to pregnant women in the second or third trimester of pregnancy, so that the antibodies reach the fetus through the placenta and the newborn will be protected during the first months.
“Maternal vaccination provides immunity from the moment of birth,” when the baby cannot yet be vaccinated, Swanson explained. “Although we see the expected decline in antibody level over time, the level at six months remains above what is necessary to provide protection.”
The vaccine has reduced serious respiratory infections due to RSV by 82% in the first three months of life
In an independent clinical trial with 37,631 participants over the age of 60, Pfizer’s vaccine has reduced cases of serious illness caused by RSV by 86% in this age group.
The results of both clinical trials have been submitted to the European Medicines Agency (EMA) and the US Food and Drug Administration (FDA) to request approval of the vaccine for pregnant women and those over 60 years of age.
Pfizer expects the US to approve the vaccine for seniors in May and for pregnant women in August, Swanson reported. In Europe, he added, “we are in a priority review process and we hope to launch it in the fall.”
The company is preparing to distribute the vaccine as soon as it is approved. “Production has already started,” said Andrew Widger, a company spokesman.
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The company GSK has also requested the approval of a vaccine against RSV in the US and Europe, but not to prevent infections in children, but only for people over 60 years of age. Other companies with ongoing RSV vaccine clinical trials include Moderna, Janssen, and Bavarian Nordic.
Although RSV was discovered in 1956 and immediate attempts were made to develop vaccines against it, efforts for decades were unsuccessful. The situation changed in 2013 when the structure of the protein that RSV uses to enter human cells was discovered. That discovery revealed the target of the virus that could be blocked and marked the beginning of a race between pharmaceutical companies to obtain effective and safe vaccines.
“The approval of the first effective and safe vaccine against RSV will be a historic milestone and a decisive step in the fight against a virus that causes nearly 100,000 deaths in the child population each year, mostly in very young babies”, assesses Quique Bassat , pediatrician and epidemiologist at the Barcelona Institute for Global Health (ISGlobal). “It was a long-awaited vaccine. We want it to be quickly accessible around the world, since RSV mortality is highest where health systems are weakest.”
Declaration of transparency: ‘La Vanguardia’ has attended the meeting of those responsible for the Pfizer vaccine program with journalists in Puurs (Belgium) invited by the pharmaceutical company
