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TThe leading cause of infant hospitalization in the United States and Europe is a virus you’ve probably never heard of: RSV. Most people experience it as a mild infection resembling a cold. But it can be very serious in babies and the elderly. Telltale symptoms are abnormally rapid breathing, sagging of the chest between and below the ribs, and wheezing or crackling sounds – disturbing noises caused by inflammation of the bronchi or the small air sacs in the lungs filling up. of liquid. The virus makes breathing and feeding, two essential activities, more difficult, but even more so for newborns.

The gap between public awareness of RSV and the harmful consequences of this virus is enormous. Worldwide, it is estimated that 64 million people become infected with RSV each year, causing approximately 160,000 deaths. And it is the most common cause of lower respiratory infections in young children worldwide, killing around 13,000 infants under six months and around 101,000 children before the age of five. In the UK, around 33,500 children under the age of five are hospitalized with RSV each year, resulting in 20 to 30 deaths. Although we tend to hear less about it, the burden on the NHS of dealing with RSV in children is greater than that of flu.

It is difficult to completely avoid RSV since it is easily spread through coughing, sneezing and infected surfaces. And it can affect any infant; the majority of hospitalizations, about 80%, involve otherwise healthy babies. For decades, pediatricians have had to rely on medical interventions to treat sick babies, such as giving them oxygen, rather than having a scientific tool to prevent them from getting sick. But the last two years have seen two major scientific advances in reducing RSV-related illness and mortality.

First, a new monoclonal antibody drug was approved in the UK and US, giving babies temporary immunity to RSV. In clinical trials, nirsevimab was about 77% effective against hospitalizations and cases of RSV requiring medical intervention. An independent international study found that babies who received a single dose of nirsevimab had an 83% reduction in hospitalizations compared to babies who received standard care.

This is an astonishing drop. Based on these findings, the U.S. Centers for Disease Control now recommends that all infants younger than eight months of age at the start of the RSV season (winter) receive nirsevimab.

Second, an RSV vaccine given to pregnant women has been approved in the United States and the United Kingdom. A clinical trial found that for mothers vaccinated between the 24th and 36th weeks of their pregnancy, the vaccine was about 82% effective in preventing severe illness in infants during the first three months after birth. This protection rate fell to 69% six months after birth.

The vaccine works by containing a laboratory-made version of an RSV surface (F) protein that invades host cells. As a result, the vaccinated adult produces F-blocking antibodies that can prevent infection, which are transmitted to the fetus via the placenta in late pregnancy. These maternal antibodies protect babies during the first months of life, while their own immune systems develop.

In Britain, the Joint Committee on Vaccination and Immunization (JCVI), which advises the government, considered both products suitable for a universal program and noted that it had no preference for the one or the other intervention. The JCVI recommended that “a cost-effective RSV vaccination program be developed for both infants and the elderly”. But integrating these treatments into the NHS presents big challenges. Dr. Ting Shi, a global RSV expert, told me that price is the main obstacle: In the United States, the price of nirsevimab is between $300 and $500 per dose, while the maternal vaccine costs around $320. dollars per dose.

Difficult negotiations with pharmaceutical companies are needed to bring prices down to make these remedies available to the British public. Galicia, Spain, is the first place to add nirsevimab to its vaccination program, meaning that all infants born during the RSV season (between September 25, 2023 and March 31, 2024) will be vaccinated with hospital within 24 hours of their birth. France is planning a similar rollout, and Belgium, Italy and Luxembourg are recommending it, although they also face the cost challenge. While high-income countries struggle to find funds, the situation is even more difficult in low-income areas, where the majority of child deaths from RSV occur.

These are logistical and policy challenges that can be solved: The important news is that there are two new tools to prevent babies from having trouble breathing and being admitted to hospital. RSV has also been a major contributor to the annual winter crises in the NHS, when rising infection rates for many diseases threaten to overwhelm the overburdened service. If these drugs are deployed quickly and effectively, RSV in young children could be virtually eliminated from the equation. This is good news and another victory for science.