New COVID-19 vaccine recommendations, data on after-effects of infection

The CDC newly recommended last week that adults ages 65 years and older receive an additional booster dose of the 2023-2024 COVID-19 vaccines. The recommendation was made by the Advisory Committee on Immunization Practices and endorsed by CDC Director Mandy Cohen, MD, MPH, on Feb. 28. "Most COVID-19 deaths and hospitalizations last year were among people 65 years and older. An additional vaccine dose can provide added protection that may have decreased over time for those at highest risk," said Dr. Cohen in an CDC press release. Patients with immunocompromise are already eligible for additional doses, the release noted.

The CDC also released new recommendations for respiratory viruses on March 1, removing its five-day isolation guidance for those diagnosed with COVID-19. For all respiratory viruses, including respiratory syncytial virus, COVID-19, and influenza, the CDC suggests returning to normal activities when symptoms have been improving for at least 24 hours and when a fever is no longer present without use of a fever-reducing medication.

In addition, the CDC published updated data on the effectiveness of COVID-19 vaccines. A study in MMWR on Feb. 29 looked at the effectiveness of a COVID-19 vaccine dose among adults in September 2023 to January 2024. It found that vaccination was 51% (95% CI, 47% to 54%) effective against ED or urgent care encounters for COVID-19 during the first seven to 59 days after receiving an updated dose and 39% (95% CI, 33% to 45%) effective in the 60 to 119 days after. Effectiveness against hospitalization was 52% (95% CI, 47% to 57%) in one CDC network and 43% (95% CI, 27% to 56%) in another, at a median of 42 and 47 days after vaccination, respectively. The results support current CDC recommendations, the authors said, adding that everyone ages six months and older should receive an updated 2023-2024 COVID-19 vaccine.

Small deficits in cognition were found in patients who had COVID-19 infection, according to a study published by the New England Journal of Medicine on Feb. 29. The results of online cognitive assessments by 112,964 participants showed that those who had been infected with SARS-CoV-2 had small deficits in global cognition compared to those who had not been infected; the results were similar between those whose symptoms had resolved in less than four weeks versus lasted at least 12 weeks. Larger deficits were found in patients with unresolved persistent symptoms after COVID-19 and in patients who had been hospitalized. The study authors calculated that the average decline would be equivalent to about three IQ points. They cautioned that the results may have been affected by participants' self-selection bias and that the implications of these findings remain unclear.

An accompanying editorial highlighted some of the uncertainties about the results. "For example, what are the functional implications of a 3-point loss in IQ? … The effects on educational attainment, work performance, accidental injury, and other activities that require intact cognitive abilities should also be evaluated," the editorialists wrote. They also noted that the pandemic "disrupted many facets of our lives" and that research needs to disentangle the effects of the infection from those of social isolation, grief, and trauma.

Finally, a study published by Annals of Internal Medicine on March 5 found that COVID-19 infection is associated with a higher risk of developing autoimmune inflammatory rheumatic diseases (AIRDs). Researchers used a claims-based database with more than 10 million South Korean patients to propensity score-match those who had COVID-19 to similar flu patients and uninfected patients. They found a significant increase in AIRD incidence after COVID-19 compared with both uninfected patients and flu patients (adjusted hazard ratios, 1.25 [95% CI, 1.18 to 1.31] and 1.30 [95% CI, 1.02 to 1.59], respectively). An analysis of 12 million Japanese patients showed similar results. The risk for AIRD was higher with more severe acute COVID-19 and lower with vaccination. "Care strategies for patients who survive COVID-19 should pay close attention to manifestations of AIRD, particularly after severe COVID-19," said the study authors.