Studies find monoclonal antibodies and remdesivir effective, while vaccine-associated myocarditis is rare

A trial of casirivimab plus imdevimab indicated it reduced risk of hospitalization or death, the CDC urged vaccination during pregnancy and updated its v-safe tool, and an analysis showed that postvaccine myocarditis occurred in men and resolved with conservative treatment.

An industry-funded phase 3 trial showed that the combination of monoclonal antibodies casirivimab and imdevimab (sold under the name REGEN-COV) reduced the risk of hospitalization or death among nonhospitalized COVID-19 patients. The study, published by the New England Journal of Medicine on Sept. 29, found lower rates of this composite outcome in patients given a 2,400-mg dose versus placebo (1.3% vs. 4.6%) and those given a 1,200-mg dose versus placebo (1.0% vs. 3.2%). The median time to resolution of symptoms was four days shorter with the antibody drug. The effects were seen in various subgroups, including patients who were SARS-CoV-2 serum antibody-positive at baseline. The study authors noted that the small number of deaths in the trial limited its ability to show an effect on mortality. In other news of monoclonal antibodies, on Sept. 29, the NIH updated its treatment guidelines to support use of bamlanivimab plus etesevimab as postexposure prophylaxis in high-risk patients.

The effectiveness of remdesivir was supported by an industry-funded, observational database study published by Clinical Infectious Diseases on Oct. 1. It matched 28,855 hospitalized COVID-19 patients who received remdesivir to 16,687 who did not and found that mortality at both 14 and 28 days was significantly lower in the former group: 10.6% versus 15.4% and 15.4% versus 19.1%, respectively.

On Sept. 29, the CDC issued an urgent health advisory to increase COVID-19 vaccination before or during pregnancy. According to the agency's data, only 31% of pregnant people have been vaccinated against COVID-19 and vaccination rates vary markedly by race and ethnicity. The disparate impact of the pandemic by race was highlighted in a study published by Annals of Internal Medicine on Oct. 5. It found that death rates from COVID-19 and several other diseases were significantly elevated in Black, American Indian/Alaska Native, and Latino populations, “sounding the alarm” about the need to address structural racism, as an accompanying editorial said.

ACP is encouraging internists to introduce their patients to v-safe, the CDC's smartphone-based tool that patients can use to report how they are feeling after vaccination. Patients can register in v-safe after any dose of COVID-19 vaccine, and it is available in English, Korean, simplified Chinese, Spanish, and Vietnamese. V-safe has new features including allowing parents to enroll dependents between the ages of 12 and 17 years and enabling people who have already been vaccinated to enter an added dose. The CDC offers print materials to distribute and display at vaccination sites, including information sheets and posters that provide a description of v-safe and a step-by-step sign-up guide. Recent data from v-safe, published in the Oct. 1 MMWR, found similar rates of local or systemic reactions to a third dose of an mRNA COVID-19 vaccine as to the second dose. Of 12,591 v-safe registrants who completed a health check-in survey after all three doses, 79.4% and 74.1% reported local or systemic reactions, respectively, after the third dose compared to 77.6% and 76.5% after the second dose, respectively.

The incidence of myocarditis after COVID-19 vaccination was described in a research letter published by JAMA Internal Medicine on Oct. 4. The study followed more than 2 million patients of a Southern California health system for six months after vaccination. There were 15 cases of confirmed myocarditis (2 after a first dose and 13 after a second, 8 with the Pfizer-BioNTech vaccine, 7 with Moderna). All were in men, with a median age of 25 years. Symptoms resolved with conservative inpatient management in all cases. Researchers calculated the incidence of myocarditis to be 5.8 cases per 1 million after the second vaccine dose (1 case per 172,414 fully vaccinated patients), which was 2.7 times that in 1,577,741 unvaccinated patients used as a comparison group. “Overall, vaccination-related myocarditis was a rare and mostly mild adverse event,” observed an accompanying editorial.