Researchers may have ideas on how to manage a deadly respiratory illness.
The illness is not influenza or COVID-19, but a respiratory syncytial virus (RSV).
Jim Boonyaratanakornkit, a virologist and transplant immunologist at the Fred Hutchinson Cancer Center in Seattle, believes the virus was first discovered in 1957 in Baltimore.
People aged 60 and older may soon be able to get some HIV protection. A committee of experts recommended that a GSK-made vaccine against RSV be approved for use. The decision will be submitted to the European Commission for final approval.
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There are no specific antiviral medications to treat RSV in the United States, and only one preventive therapy — a monoclonal antibody — is reserved for a small number of infants at high risk of severe illness. But that may soon change. Several companies now have clinical research data suggesting that their various vaccine candidates or lab-made monoclonal antibodies can protect against the worst effects of RSV.
Researchers reported last year that RSV affected one in every 28 deaths of children aged 28 days to 6-months-old.
Penny Heaton of Janssen Pharmaceuticals, a Johnson & Johnson subsidiary, said at the World Vaccine Congress, held April 4 in Washington D.C. “This is the incredible impact that... RSV vaccinations [and] monoclonal antibodies [can have] on children's health internationally.”
The 5-and-under crowd will be affected. Their grandparents, great-grandparents, and other older adults may soon receive RSV injections. That might result in an decrease in the burden of RSV in the two populations affected the most.
GSK, previously GlaxoSmithKline, and Pfizer are on the verge of getting approved by the Food and Drug Administration for their RSV vaccines. Moderna is on the verge of becoming the first Danish company to conduct a clinical trial for its vaccine. Other companies are also testing RSV vaccinations.
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Other companies are developing monoclonal antibodies to administer to babies and infants as preventives against RSV. They aren't vaccines, but a dose administered before the start of RSV season might temporarily protect vulnerable babies from becoming very sick if they get infected.
Janssen has decided to pull out of its RSV program and stop a late-stage clinical study. The company also announced the decision in March, claiming it would focus on unmet medical needs.
The virus is still a concern for the time being. The typical RSV season starts in October and peakes in December or January — at least in the United States. It usually finishes in April.
RSV-positive PCR tests never increased above 3% in the first year of the COVID-19 epidemic, according to the US Centers for Disease Control and Prevention. RSV-positive PCR tests rose from about 13 to 16 percent before the COVID-19 epidemic.
Researchers predict the virus to arrive in the summer of 2021, according to the Morbidity and Mortality Weekly Report. That year, the RSV season shifted, starting in May. It reached its zenith in July and ended in January 2022.
The 2022–23 RSV season shifted closer to the prepandemic cycle, but was still early. The 2022 season began in June and reached its peak in November, depending on which part of the country you live in. Children have been impacted by this latest RSV season, which lasted between December and February.
No one knows when the next RSV season will begin. However, some of the new medicines and therapies are expected to be available this fall, potentially reducing doctor visits, hospitalizations, and fatalities due to the infections.
Here's a list of the vaccine and treatment candidates.
Pfizer, GSK, and Moderna have based their vaccines on an element of the virus, the F protein, which protects the virus from the outer membrane and aids in its attachment to human cells. The F protein is a shapeshifter. Before fusion, it looks like a round knob. After fusion, it looks like a needle or pointy tower.
Researchers at the National Institutes of Health in the United States discovered that locking the protein in its prefusion knob state results in the immune system reacting more effectively than to the virus' shapeshifting form. Pfizer described the nitty-gritty details in Science Translational Medicine.
The proteins in Pfizer and GSK's vaccinations are the protein itself. Moderna's candidate, like the COVID-19 vaccine, is an mRNA vaccine that tells the body to produce the protein.
Bavarian Nordic is taking a different approach. It develops a live vaccinia virus, a pox virus that can't reproduce very well in the body, such as many flu, measles, and chicken pox vaccinations.
Bavarian Nordic made the vaccinia virus to produce five of the virus's proteins, including the F protein, during the World Vaccine Congress. However, the company has no data yet to demonstrate that the vaccine would protect against all three diseases, according to Peter Costa, Bavarian Nordic's regional director for medical affairs in the United States.
Codagenix, another company, is experimenting with the RSV virus as it is made, altering its genetic instruction manual to make it unusable for disease. According to Jeffrey Fu, the company's chief business officer, those changes alter the virus's RNA, but they don't alter the amino acids in its proteins.
"We're able to construct viruses... that look identical or nearly identical to the actual virus," Fu told me. Because the virus replicates slowly, it does not cause illness but stimulates an immune response, unlike the other vaccinations, which are administered as drops.
Codagenix intends to begin testing its vaccine's safety at a low dose in healthy 5-year-olds this spring. If the vaccine is safe, the company will gradually increase the dosage as well as begin testing the vaccine candidate in younger children, starting with 6-month-olds.
The remainder of the companies' vaccines are for use in older adults.
Only Pfizer is working on a vaccine to protect newborns. It doesn't administer injections to babies; rather, it provided its candidate to more than 7,300 healthy pregnant women aged 49 or younger. The idea is that the mother will produce antibodies against RSV that will pass through the placenta to the baby.
RSV may be just a coldlike illness for many kids, with a runny nose, a cough, and difficulty breathing. Very young infants may stop breathing for longer than 10 seconds.
Researchers reported on April 5 that Pfizer's strategy to help babies recover from the effects of RSV seemed to have worked. Six infants born to mothers who got the vaccination developed severe RSV lung infections that required medical treatment. 33 babies in the placebo group developed severe lung infections, according to researchers.
As mothers' antibodies wore out, the vaccine effectiveness slowed. Within six months after birth, 19 babies of mothers in the vaccination group and 62 infants of mothers in the placebo group developed severe lung infections, a vaccine efficacy of about 69%.
Although the vaccine failed to meet statistical standards for less-severe lung illnesses, there were only about half the number of such infections in infants who received the vaccine than those who received a placebo. Within 90 days after birth, 24 infants in the vaccinated-mom group and 56 in the placebo group developed lung infections, which increased to 51%.
The vaccine kept babies out of the hospital as well. In the first 90 days of life, the vaccine's effectiveness was about 68%, before declining to about 57% within 180 days of birth.
The vaccine wasn't particularly effective against any RSV illness that required medical treatment, like the COVID vaccines and most vaccines for respiratory illnesses (SN: 5/29/22). The vaccine's efficacy against any RSV illness that required medical attention was about 39 percent in the first three months of life and 38 percent in the six months after birth.
At the vaccine congress, Barbara Pahud, the clinical director for Pfizer's ongoing research, said there were no significant adverse effects beyond what researchers anticipated.
According to Pfizer, the company is continuing to monitor the children and will have two years of data to present ahead of an FDA meeting to discuss the vaccine's approval in August.
Giving an RSV vaccine to pregnant women protected their infants from severe RSV lung illnesses that required medical treatment. The vaccine's effectiveness was 88% in the first 90 days after birth, but it was still more than 69% effective six months after birth.
Codagenix has data from lab animal trials that show that its vaccine may induce protective antibodies. However, its study in children is just getting underway, and there are no conclusions to be reported yet.
Giving monoclonal antibodies to newborns and babies might help against RSV as well. Laboratory-made antibodies targeted against the virus's F protein are showing some signs of success in protecting infants against the virus.
Palivizumab, a monoclonal antibody, was approved by the FDA in 1998. That includes babies who were born prematurely, those with a chronic lung illness called bronchopulmonary dysplasia, and infants with certain cardiac conditions. And palivizumab isn't available in most low- and middle-income countries where the virus is the biggest problem, according to Codagenix.
Palivizumab isn't very long lasting. During the RSV season, vulnerable babies need an injection every month. The medication is also costly.
Sanofi and AstraZeneca teamed up to produce one called nirsevimab, which was approved for use in the European Union and the United Kingdom in November, and is being considered for adoption in the United States.
Researchers reported that nirsevimab worked well against hospitalization for about 2,000 newborns in a clinical study, and a placebo for about 1,000 babies. The difference between the two was 768 percent.
Merck is also undergoing clinical testing of a long-lasting monoclonal antibody. The findings from those studies are yet to be released.
When it comes to RSV, babies, toddlers, and preschoolers are probably the most feared groups, but older people are also at high risk.
The CDC estimates that between 60,000 and 160,000 older adults are hospitalized with RSV each year, and 6,000 to 10,000 people die. Researchers reported last year in Influenza and Other Respiratory Viruses that 5.2 million people ages 60 or older were hospitalized, with about 33,000 people dying, according to the researchers.
Edward Walsh, an infectious diseases doctor at the University of Rochester Medical Center in New York, spoke at the World Vaccine Congress on April 5th.
Walsh was one of the key researchers who tested Pfizer's vaccine for older adults in a multimillion-dollar research conducted in Argentina, Canada, Finland, Japan, the Netherlands, South Africa, and the United States. Half of the participants received the vaccine candidate, while half received a placebo.
Walsh said the RSV came back in large numbers in older adults, especially not in the over-60 crowd, and they continued to wear masks, preventing transmission.
Walsh said later that he and his colleagues found only 16 percent of prepandemic infections in older adults in the Rochester region during the study period. "We were very hesitant that the experiment would reveal anything."
The Rochester region was just one of 240 sites covered by the study. With the data collected from each location, the researchers had enough data to determine the vaccine's effectiveness. Different levels of severity based on whether the virus infected the lungs and how many symptoms, such as cough, wheezing, or shortness of breath, participants reported.
Walsh and colleagues reported that the vaccine had an effectiveness of 68.7% against RSV lung infections with three or more symptoms in the placebo group.11 In the vaccination group.
The efficacy ratings are lower, but similar to those reported by GSK on February 16 in the New England Journal of Medicine. However, the data from the vaccination studies aren't directly comparable because they were conducted in different countries and used different methods.
GSK tested its vaccine on around 25,000 people aged 60 and over from 17 countries across five continents. Seven individuals who received the company's vaccine and 40 who received a placebo developed RSV lung infections with two or more symptoms lasting at least 24 hours, according to the European Medicines Agency's committee for human medicines.
Moderna hasn't published the results of its vaccination study in a scientific or medical journal, but it issued a press release in January with the numbers. About 37,000 adults aged 60 and older in 22 countries received the vaccine or a placebo, for an effectiveness rate of 83.7 percent.
Bavarian Nordic administered an RSV vaccine to healthy 18- to 50-year-olds in a human challenge experiment (SN: 2/18/21). The vaccine prevented symptomatic infections with a 99% effectiveness rate, but that was among healthy younger adults who had less risk of serious complications than elderly people.
Bavarian Nordic also conducted a clinical investigation with 20,000 people aged 60 and older in the United States and Germany. The results of the study should be available later this year, according to Costa.
RSV is unlikely to dissipate once more, thanks to masking and social alienation. New vaccinations and monoclonal antibodies, will not stop the spread of RSV. However, they may at least help those who are most vulnerable to the virus's harmful effects.
