COVID-19: Antibody Test Accuracy / Microwaving N95 Masks / Pregnancy / Tocilizumab / Neurologic Complications

By Amy Orciari Herman

NEJM Journal Watch

Edited by André Sofair, MD, MPH, and William E. Chavey, MD, MS

Check out some of the latest developments on COVID-19:

Antibody test accuracy: Tests for IgG/IgM antibodies against SARS-CoV-2 have a sensitivity of just 30% during the first week of symptoms, rising to 91% during the third week, according to a review of 38 studies published by Cochrane Library. Data beyond 3 weeks were limited. Overall, test specificity was above 98%. The researchers say that while antibody tests “may still have a role complementing other testing in individuals presenting later, when RT‐PCR tests are negative, or are not done,” the limited data beyond 3 weeks calls into question “the utility of these tests for seroprevalence surveys for public health management purposes.” Of note, the evaluated tests included both point-of-care and laboratory-based tests.

Microwaving N95 masks: Researchers have devised a way to decontaminate N95 respirators using household supplies: glass containers, mesh from produce bags, a rubber band, and a microwave. Not only did their microwave-steaming method decontaminate respirators after one 3-minute treatment, but the respirators’ fit and function were maintained after 20 decontamination cycles. Metal within the masks did not spark during treatment. The researchers write, “This method provides a valuable means of effective decontamination and reuse of N95 respirators by frontline providers facing urgent need.”

Outcomes in pregnancy: Pregnant women infected with SARS-CoV-2 face higher risk for severe outcomes than their nonpregnant peers, according to an analysis of 8200 infected pregnant women and 83,000 infected nonpregnant women in MMWR. Overall, the ICU admission rate was 1.5% among the pregnant cohort versus 0.9% among the nonpregnant cohort, and the mechanical ventilation rate was 0.5% vs. 0.3% — both significant differences. Mortality rates, however, did not differ. The authors conclude that “measures to prevent infection with SARS-CoV-2 should be emphasized for pregnant women and their families.”

Tocilizumab: The monoclonal antibody tocilizumab might improve outcomes in patients with severe COVID-19 pneumonia, according to a retrospective study in The Lancet Rheumatology. Researchers in Italy studied 365 patients who received standard care alone and 179 who also received tocilizumab (intravenously or subcutaneously). After multivariable adjustment, the tocilizumab group had a 39% lower risk for the primary composite outcome of death or need for mechanical ventilation. However, tocilizumab was associated with new-onset infections (e.g., invasive aspergillosis).

Neurologic complications: In The Lancet Psychiatry, U.K. researchers detail the results of a nationwide surveillance study of neurologic complications of COVID-19. Of 153 such cases identified in April, 125 had complete data available. Cerebrovascular events (in particular, ischemic strokes) were most common, followed by altered mental status (e.g., encephalopathy, encephalitis). About half the patients with altered mental status were younger than 60.