Over 600K COVID-19 Breakthrough Infections Confirmed in People with Immune System Dysfunction

A team of U.S. researchers reported today in the JAMA Internal Medicine the risk of COVID-19 breakthrough infection was much higher among fully vaccinated people with immune dysfunction.

In this Original Investigation study of 664,722 patients who received at least one dose of a COVID-19 vaccine, those with an HIV infection, rheumatoid arthritis, and solid organ transplant had a higher rate for COVID-19 breakthrough infection.

Overall, the incidence rate for COVID-19 breakthrough infection was 5 per 1,000 person-months among fully vaccinated persons but was higher after the Delta variant became the dominant SARS-CoV-2 strain.

After June 20, 2021, the breakthrough case rate was 7.3 [95% CI, 7.3-7.4] per 1,000 person-months.

After full vaccination, people with a breakthrough infection were more likely to be older (51 yrs.) and women (57%).

Furthermore, people with HIV infection, rheumatoid arthritis, and solid organ transplant had a higher breakthrough infection rate.

The retrospective cohort study analyzed data from the National COVID Cohort Collaborative, an electronic medical record-based repository of COVID-19 clinical data.

The study included all patients who had received at least one dose of a COVID-19 vaccine from Dec 10, 2020, through Sep 16, 2021.

Full vaccination was defined as completing the recommended dosing regimen of any U.S. Food and Drug Administration authorized COVID-19 vaccine.

During the study's evaluation period, the mRNA Comirnaty and SpikeVax vaccines were most often administered in the U.S.

Breakthrough infection was defined as a COVID-19 infection contracted on or after the 14th day of vaccination.

For persons with immune dysfunction, continued use of nonpharmaceutical interventions (e.g., mask-wearing) and alternative vaccine strategies (e.g., additional doses) or immunogenicity testing are recommended even after full vaccination.

The study authors note that the observed breakthrough infection rate is higher than reported by the Centers for Disease Control and Prevention surveillance data.

Note: This study did not include SARS-CoV-2 virus variant Omicron breakthrough infection data.