'Risks of Respiratory Virus Vaccines for Immunocompromised Patients'

 When it comes to questions about respiratory virus vaccination in immunocompromised children and adults, the answers may be clearer than many clinicians think, according to a panel of infectious disease experts.

In a presentation, the Infectious Diseases Society of America (IDSA) outlined key points from their guidelines on COVID-19, influenza, and respiratory syncytial virus (RSV) vaccination in immunocompromised patients.

"Our patients with weakened immune systems are particularly vulnerable to more severe infection and associated complications," said Lindsey Baden, MD, vice president of clinical research at Brigham and Women's Hospital in Boston. "We need data-driven prevention strategies to guide how to protect our patients."

The panel's recommendations build on a recent systematic review of 511 studies that showed immunization against COVID, RSV, and influenza effectively and safely reduced the risk of severe outcomes in people of all ages.

COVID Vaccination: ASAP

In adults and kids with compromised immunity, the answer is clear: vaccinate as soon as possible. COVID vaccination is shown to reduce associated hospitalizations in this population, with vaccine effectiveness ranging from 33% to 56% in studies.

"We recommend age-appropriate 2025-2026 COVID-19 vaccinations -- a strong recommendation with moderate certainty of evidence," said Anoma Nellore, MD, associate director of translational research at the NYU Langone Health Vaccine Center in New York City. A second dose may extend protection, she added. Everyone in an immunocompromised patient's household should also receive a COVID vaccine.

For immunocompromised patients who've never had a COVID shot or only had an incomplete series, guidelines from the Advisory Committee on Immunization Practices published in 2024 should be followed. Patients can safely get all three respiratory virus vaccines -- COVID, flu, and RSV -- together at the same time.

The IDSA guidelines offer vaccination timing advice for people with specific conditions such as solid organ transplant, hematopoietic cell transplant, and solid tumor chemotherapy.

"We recommend shared decision-making and ongoing risk assessment, recognizing that this patient population can have escalating immune compromise through their disease course," Nellore explained.

Flu Vaccination: Strong Recommendation

Immunocompromised patients have a two to four times greater risk of flu-related complications, said Paul Goepfert, MD, director of the Alabama Vaccine Research Clinic in Birmingham. For this population, hospitalization rates range from 15% to 30%, and flu-related mortality rates range from 5% to 15%.

If the risks are clear for immunocompromised patients, so are the benefits. Flu vaccination led to a 32% reduction in flu-related hospitalizations among the immunocompromised, and research has shown that vaccination doesn't put these patients at greater risk of adverse events such as Guillain-Barré syndrome.

The bottom line: Age-appropriate 2025-2026 flu vaccination is "strongly recommended" in children and adults with compromised immune systems, Goepfert said. That recommendation is made with moderate certainty, given that limited studies included immunocompromised patients. While research shows that high-dose or adjuvanted flu vaccines produce a more robust immune response, he noted, more data are needed on those vaccines' efficacy.

Immunocompromised patients' close contacts should also get a flu shot, Goepfert added. As with COVID vaccination, the IDSA guidelines offer flu vaccination timing recommendations for specific conditions.

RSV Vaccination: Re-Dose if Timing Is Off

All adults with compromised immunity should be vaccinated, said C. Sabrina Tan, MD, of the University of Iowa Carver College of Medicine in Iowa City. That recommendation is made with moderate certainty. For patients younger than 18, shared decision-making should determine vaccination choices.

RSV vaccination had an estimated effectiveness of 70% at preventing RSV-associated hospitalizations in immunocompromised patients, based on pooled data from two studies. Three FDA-approved RSV vaccines are available -- two protein subunit vaccines (Arexvy and Abrysvo) and a new mRNA vaccine.

Defer RSV vaccination during an acute illness, Tan cautioned, and consider getting vaccinated during periods of high community transmission, such as the winter. If a patient gets the RSV shot earlier than the traditional RSV season, consider administering another single dose during the regular RSV season, she said.

Pediatric Considerations: 'Bubble of Protection'

Respiratory virus vaccinations are critical in preventing hospitalization in immunocompromised children. "But there are distinct features of a child's immune system that we need to take into consideration" when making vaccination decisions, said Tanvi Sharma, MD, MPH, clinical director of the division of infectious diseases at Boston Children's Hospital.

Many of the immunocompromising conditions in adults may be more pronounced in children, Sharma noted, and young children have no pre-existing immunity to many pathogens. That makes the potential for more severe outcomes "substantial," she added.

COVID and flu vaccinations are recommended for immunocompromised children ages 6 months and older, Sharma said. For those younger than 6 months, she noted, "the best protection for them is in ensuring that their close contacts -- parents, siblings, and other household members, babysitters, daycare staff, healthcare providers -- are also fully vaccinated to create a bubble of protection around these children who may not be eligible for vaccination yet."

While RSV vaccines aren't approved for children, the approved RSV monoclonal antibodies clesrovimab (Enflonsia) and nirsevimab (Beyfortus) should be given to immunocompromised infants up to age 20 months.

https://www.medpagetoday.com/infectiousdisease/vaccines/119179