By Anna Tsioulias
Although underlying conditions can increase the risk for hospitalization for COVID-19, age and vaccination status remain strong factors associated with the likelihood that a person will be hospitalized, according to data presented at the CDC’s Advisory Committee for Immunization Practices (ACIP) meeting.
As a result, the ACIP continued to support vaccination against COVID-19. In a unanimous vote, the committee voted to recommend the 2024-2025 COVID-19 vaccines authorized or approved by the FDA for people ages 6 months and older.
Hospitalizations are down since the early days of the pandemic, but adults 65 years and older make up 67% of these hospitalizations, while those younger than 65 made up 33% of COVID-19 hospitalizations. Older people fared even worse, with 46% of those 75 and older being hospitalized.
Only 11% of hospitalized adult patients between October 2023 and March 2024 had received the 2023-2024 COVID-19 vaccine prior to admission.
Although the disease tends to be milder in children, 4% of hospitalizations occur among those 17 years and younger, according to Fiona Havers, MD, MHS, FIDSA, a medical officer in the CDC’s Division of Viral Diseases, who provided an update about the disease.
Rates were highest among infants 6 months and younger, who are not eligible for COVID-19 vaccination, which lends support for the vaccination of pregnant women to protect their infants.
“Infants less than 6 months had recent cumulative hospitalization rates that were approximately six times that of hospitalization rates in children ages 6 months to 4 years, the pediatric group with the second-highest rates,” Dr. Havers said. Another interesting finding was that 50% of the children who were admitted to the ICU had no underlying medical conditions that could have predisposed them to hospitalization, according to Dr. Havers.
As for vaccine effectiveness, Ruth Link-Gelles, PhD, MPH, an epidemiologist at the CDC, highlighted the increased protection against SARS CoV-2 infection and COVID-19−associated emergency department or urgent care visits and hospitalizations among vaccinated people compared with those who did not receive the 2023-2024 vaccine dose. The effectiveness of the 2023-2024 vaccine was similar across age groups and provided protection against JN.1 and other circulating variants, although it may be lower than protection provided against the XBB sublineage variants.
Additionally, “waning patterns appeared similar to previous COVID-19 vaccine formulations, and most durable protection appeared to be for critical illness,” Dr. Link-Gelles said.
As more people recover from infection and are vaccinated, it becomes difficult to clarify the true efficacy of vaccination, according to Sarah Long, MD, an attending infectious disease physician at St. Christopher’s Hospital for Children, in Philadelphia.
“It gets to be a very difficult thing with a virus that’s mutating all the time to try to understand if more and more immunizations are going to be helpful,” Dr. Long noted, although she did vote in favor of continued vaccination at this time.
She was also surprised to learn about the pattern of COVID-19−related hospitalizations, with cases occurring all year rather than during the traditional respiratory season. “The other problem I didn’t know about … is that the hospitalizations looked like they were in every month; it wasn’t all so seasonal as I thought it probably would have been,” Dr. Long said.
The vaccine safety update for the 2023-2024 COVID-19 vaccine highlighted the two statistical signals identified by the Vaccine Safety Datalink (VSD): Guillain-Barre syndrome and ischemic stroke.
Out of almost 2.5 million doses of the Pfizer-BioNtech vaccine and 239,660 doses of the Moderna vaccine, VSD identified a signal for GBS among recipients 65 years and older, with an estimated excess cases of 4.1 per 1 million doses of the Pfizer vaccine.
“The increased rate ratio of GBS following the Pfizer COVID-19 vaccine among people aged over 65 observed during the 2023-2024 season may or may not represent a true risk,” said presenter Jonathan Duffy, MD, MPH, CDC Immunization Safety Office. “If there is a true risk, the estimated excess GBS cases of 4.1 per million doses is similar to previous estimates for other vaccines for adults.”
For example, influenza vaccine has one to two cases per 1 million doses.
As for ischemic stroke, Dr. Duffy reported that the VSD statistical signals after mRNA COVID-19 vaccines during the 2023-2024 season do not provide sufficient evidence to conclude that there is a safety concern.
The vaccines will be available to ship potentially in mid-August to late September contingent on FDA authorizations, and the orders are anticipated to reach physician offices one to two weeks after FDA action, according to Shannon Stokley, DrPH, an epidemiologist at the CDC.
“We do expect that insurance plans will cover the [2024-2025 COVID-19] vaccine immediately because of the Affordable Care Act that requires insurers to cover most ACIP-recommended vaccines without cost sharing as well as the CARES act, which provides included provisions to expedite coverage of COVID vaccines when they become available,” Dr. Stokley said. Additionally, Medicaid and Medicare will cover COVID-19 vaccines without cost sharing.
