COVID-19 Roundup: Incubation, Liver Tests, Mouthwash
Incubation Period
Researchers from the US NIAI/NIH, Peking University, and the Chinese Center for Disease Control and Prevention have a new estimate for the incubation period of COVID-19, following an analysis that used renewal theory and data from 1084 confirmed cases with connections to Wuhan, China.
The new estimated median time of incubation, 7.76 days, is longer than the previously estimated median of 4 to 5 days. The researchers estimated the mean as 8.29 days, the 90th percentile as 14.28 days, and the 99th percentile as 20.31 days.
Liver Tests
Researchers from the Yale Liver Center have uncovered a link between COVID-19 and higher rates of abnormal liver tests. Higher levels of liver enzymes were also shown to be associated with worse outcomes among patients with COVID-19.
While previous studies of patients in China suggested that about 15% of patients with COVID-19 had abnormal liver tests, the Yale study, which used data from 1,827 patients hospitalized between March and April 2020, found that the number could actually be as high as 83.4%.
As for why these rates would differ so much between Chinese and American patients, the researchers suggested that US patients could have greater rates of risk factors for liver disease than do Chinese patients. They also noted a strong relationship between the drugs used to treat COVID-19 and liver damage.
Mouthwash
According to the results of cell culture experiments by Virologists from Ruhr-Iniversitat Bochum, certain common, commercially available mouthwashes are able to inactivate the SARS-CoV-2 virus. This information could be useful for the prevention of COVID-19 transmission over the short term, the researchers noted, in situations like dental procedures.
They tested 8 mouthwashes available commercially in Germany, mixing them with the virus and a saliva-mimicking solution. Of the 8, 3 mouthwashes reduced levels of the virus so much that it could no longer be detected after 30 seconds of exposure. They noted, however, that further studies would be needed to assess how long this effect lasted.
COVID-19 Updates from CDC
As of July 31, 2020, the CDC has received reports of a total of 34,990,702 specimens tested for SARS-CoV-2, of which, 3,305,091 (9.4%) were positive.
Levels of influenza-like illness (ILI) are low, but high for the time of year. Levels of COVID-19-like illness have decreased since the previous week, with nearly all regions showing decreases or stable levels.
Overall, the cumulative COVID-19-associated hospitalization rate is 137.6 per 100,000. Rates are highest among individuals aged 65 years and older (378.8 per 100,000) and 50-64 years (207.4 per 100,000). Weekly hospitalization rates decreased during week 31 but are subject to change as more data becomes available.
Percentages of deaths attributed to pneumonia, influenza, or COVID-19 is 7.8% for week 31, which is lower than the 12.6% seen the week before.
—Michael Potts
References:
Qin J, You C, Lin Q, et al. Estimation of incubation period distribution of COVID-19 using disease onset forward time: a novel cross-sectional and forward follow-up study. Published online August 7, 2020. Sci Adv. doi: 10.1126/sciadv.abc1202
Hundt MA, Deng Y, Ciarleglio MM, et al. Abnormal liver tests in COVID‐19: a retrospective observational cohort study of 1827 patients in a major U.S. hospital network. Hepatology. doi: 10.1002/hep.31487
Meister TL, Bruggemann Y, Todt D, et al. Virucidal efficacy of different oral rinses against SARS-CoV-2. Published online July 29, 2020. IDSA. doi: 10.1093/infdis/jiaa471
COVIDView: a weekly surveillance summary of US COVID-19 Activity. Centers for Disease Control and Prevention. https://www.cdc.gov/coronavirus/2019-ncov/covid-data/covidview/index.html. Updated August 7, 2020. Accessed August 10, 2020.