New guidelines on COVID-19 antibody testing, flu vaccination and trial data on remdesivir

The Infectious Diseases Society of America (IDSA) updated its guidelines on diagnosis of COVID-19 on Aug. 18, adding a new section on serologic testing. The IDSA suggests against serologic testing to diagnose infection during the first two weeks following symptom onset. It suggests using IgG antibody testing in symptomatic patients with a high clinical suspicion and repeatedly negative nucleic acid amplification tests. IgG or total antibody testing can also be used three to four weeks after symptom onset to detect evidence of past infection for clinical or epidemiological purposes, it said. The IDSA suggests against using IgA or IgM/IgG antibody combination tests and makes no recommendation on IgM tests. In another guideline update on Aug. 20, the IDSA also recommended against hydroxychloroquine alone or hydroxychloroquine plus azithromycin for hospitalized patients with COVID-19, saying that higher certainty benefits from these drugs “are now highly unlikely.”

Somewhat disappointing results for remdesivir came from a randomized, manufacturer-sponsored trial published by JAMA on Aug. 21. It compared 10-day (n=197) and five-day (n=199) courses of remdesivir to each other and standard care (n=200) in hospitalized patients with confirmed severe SARS-CoV-2 infection and moderate COVID-19 pneumonia. The primary end point was clinical status on day 11 on a seven-point ordinal scale. The patients getting five days of therapy had a statistically significant improvement (odds ratio, 1.65; 95% CI, 1.09 to 2.48; P=0.02) over standard care. However, those in the 10-day group did not, and the study authors concluded that the difference between the five-day and standard care groups “was of uncertain clinical importance.” An accompanying editorial noted that the data thus far on remdesivir have shown mixed results, but variations in the studies and in clinical practice make definitive conclusions difficult. “Some of the [randomized controlled trial] findings suggest remdesivir could improve recovery for many millions of individuals around the world who may be hospitalized with COVID-19. However, the costs to produce and distribute remdesivir at such scale are considerable, and, most importantly, whether remdesivir offers incremental benefit over corticosteroids, which are widely available and inexpensive, is unknown,” the editorial said.

The FDA issued an emergency use authorization for convalescent plasma to be used in hospitalized patients with COVID-19 on Aug. 23. The authorization was based on non-peer-reviewed data posted Aug. 12. Last week, the New York Times had reported that the FDA would not be approving the treatment based on top health officials concerns' that there is not sufficient evidence to support its effectiveness.

The CDC issued seasonal influenza vaccination recommendations that address the likelihood that the SARS-CoV-2 and influenza viruses will both be active in the U.S. during the upcoming flu season. The recommendations, issued by the Advisory Committee on Immunization Practices and published by MMWR on Aug. 21, call for flu vaccination of everyone six months of age and older. The CDC recommends that vaccination be offered by the end of October but notes that the circumstances of the pandemic might necessitate starting vaccination campaigns earlier (although the potential waning of protection from influenza vaccination over the season, particularly in older patients, should also be considered). The article notes that this year's vaccines include updates to the influenza A(H1N1)pdm09, influenza A(H3N2), and influenza B/Victoria lineage components and that since last year two new vaccines have been licensed for those ages 65 years and older.

Finally, a small case series study, published as a research letter by CHEST on Aug. 21, offered some good news about outcomes after ICU treatment for COVID-19. At one academic health center, all 59 patients who had been discharged from the ICU were contacted to follow up in a post-ICU clinic. By July 30, 28 patients had been seen there, and 16 of them (61.54%) had normal lung function. Four (15.38%) had obstruction, five (19.23%) had restriction, one (3.85%) had mixed obstruction and restriction, and seven (26.92%) had reduced diffusion capacity. Seven patients had mild to moderate depression. The authors noted that these outcomes were similar to those in acute respiratory distress syndrome not related to COVID-19 and the study “suggests the feasibility of an in-person outpatient clinic for post-ICU COVID-19 patients and a low burden of pulmonary and neurocognitive morbidity at immediate follow-up.”