Q&A: ‘Atypical’ increase of RSV cases in children may be due to waning immunity

CDC data have shown a spike in respiratory syncytial virus cases among children, with incidence occurring earlier in the season than what is typically seen and anecdotal accounts of pediatric hospitals reporting they are at capacity.

According to the CDC, the nationwide respiratory syncytial virus (RSV) positivity rate was 8.6% on Sept. 10, increasing to more than 15.4% by Oct. 8 this year. Further, CDC data show an RSV hospitalization rate per 100,000 of 2.6 at the end of this October, compared with rates of 1 last year, 0 in 2020 and 0.3 in 2019.

To learn more about this spike in cases and how best to identify and treat pediatric RSV, Healio spoke with Hollis Chaney, MD, pulmonologist and vice chair of the division of pulmonary medicine at Children’s National Hospital, about RSV, treatment options and prevention tips.

Healio: There are a lot of reports in the media right now about pediatric hospital beds filling up with children with RSV. Has this been your experience? If this is atypical, what might be the contributing factors for the higher incidence seen this year?

Chaney: As a pulmonologist, I have seen a marked increase in the number of patients with RSV, including in the clinic setting, emergency department, hospitalizations and in intensive care. It is very atypical, much more than in the past, and this is likely due to waning immunity. People were wearing masks and socially distancing due to COVID-19 and had less exposure to other viruses. With each virus, the body can build defenses against future infection. Because so many children younger than 3 years had minimal exposure to viruses during the pandemic, their immune system is unprepared. Now they are back in daycare and preschool and easily spreading all the germs

Healio: If children are presenting to their pediatrician’s office with illness, what symptoms should pediatricians be on the lookout for that might indicate RSV or severe RSV?

Chaney: RSV symptoms start as a cold, and in 2 to 3 days lead to lower respiratory tract symptoms, such as rapid breathing, wheezing, persistent coughing and difficulty breathing. Symptoms usually peak on days 3 to 5 and gradually resolve in 2 to 3 weeks.

Signs of severe RSV infection include retractions, nasal flaring, grunting, respiratory rate over 70 breaths per minute, cyanosis with low oxygen levels and apnea. Patients may also become dehydrated due to difficulty feeding from the nasal congestion and rapid breathing.

Healio: What standard treatments do hospitalized children with RSV receive?

Chaney: The goal is to support hydration and respiratory status as necessary. One standard treatment is nasal suctioning and oxygen to maintain oxygen saturation greater than 90% to 92%. If there is significant difficulty breathing, it may progress to respiratory failure and require high-flow nasal cannula or continuous positive airway pressure. Bronchodilators and inhaled or systemic glucocorticoids are not routinely used, especially if this is the first episode of bronchiolitis; however, they may help in older children and adults, especially if they have asthma or another chronic lung disease.

Healio: Are there any therapies under investigation for RSV that might soon become available?

Chaney: Currently, there is no specific treatment for RSV. There are observational studies for treatment in patients who are immunocompromised including a single agent or combination therapy of the following:

• nebulized or oral ribavirin, which is approved by the FDA;
• IV immune globulin (IVIG);
• palivizumab (Synagis, Sobi), an RSV-specific humanized monoclonal antibody; and
• glucocorticoids.

Healio: There have been promising data on a vaccine for older adults to prevent RSV. Do you have any insights about when such a vaccine might be available for children or for pregnant mothers?

Chaney: Palivizumab is used to prevent serious lower respiratory tract disease in children at high risk, including premature infants younger than 28 weeks gestation and some infants with chronic lung disease of prematurity or some congenital heart diseases. Nirsevimab (Beyfortus, AstraZeneca, Sanofi), a recombinant human IgG1 kappa monoclonal antibody, is still under investigation, given as a single injection.

There is an ongoing trial for a vaccine that is given to pregnant women which mounts antibodies that can cross the placenta into the fetus. NIH also has ongoing trials of live-attenuated RSV vaccines for the older infant. There are multiple RSV vaccines in trials for older adults, including a messenger RNA vaccine (similar to the COVID-19 vaccine).

Healio: What are the best means of preventing RSV among children?

Chaney: Direct contact is the most common route of transmission. RSV can survive on hands and surfaces for several hours. Studies show that infection in infants most often follows infection in older siblings, so hand washing and contact precautions are important, including:

• washing hands frequently, especially before touching an infant;
• staying away from adults and children with colds;
• keeping infants and children home from school or daycare when they are sick; and
• sanitizing high-touch areas such as toys, doorknobs, kitchen counters and bathroom sinks.

References:

• CDC. The national respiratory and enteric virus surveillance system. https://www.cdc.gov/surveillance/nrevss/rsv/natl-trend.html. Accessed Nov. 3, 2022.
• CDC. RSV-NET interactive dashboard. https://www.cdc.gov/rsv/research/rsv-net/dashboard.html. Accessed Nov. 4, 2022.