Infectious Disease

COVID-19 Roundup: Testing Donated Blood, Dexamethasone, Mosquitos

RNA Levels Following Disease Resolution

A case reported in the Annals of Internal Medicine detailed a patient and volunteer blood donor who was identified as having had upper respiratory infection in March 2020. The patient was afebrile and was not tested for COVID-19 at the time. Forty days after symptom resolution, SARS-CoV-2 RNA was detected in blood donated by the patient. Despite this, nasopharyngeal swab results were negative for SARS-CoV-2.1

“The confirmation of donor RNAemia more than 1 month after symptom resolution is concerning in light of current guidelines, which do not recommend SARS-CoV-2 screening in the general allogeneic donor population,” the authors wrote.

Dexamethasone

According to a recent study involving 2104 patients with COVID-19 assigned to dexamethasone (6 mg once per day) and 4321 patients who received usual care, use of dexamethasone resulted in lower 28-day mortality among patients who received invasive mechanical ventilation or oxygen alone, but not among patients that did not receive respiratory support.2

Mosquitos

In a recent study, researchers examined the ability of SAR-CoV-2 to replicate within 3 common mosquito species. They found that “even under extreme conditions, SARS-CoV-2 virus is unable to replicate in these mosquitoes and therefore cannot be transmitted to people even in the unlikely event that a mosquito fed upon a viremic host.”3

Oxford Vaccine

Preliminary results of a phase 1/2 trial of healthy adults suggest that a COVID-19 vaccine developed by the University of Oxford is safe and induces an immune response.4

The chimpanzee adenovirus-vectored vaccine (ChAdOx1 nCoV-19) was not associated with any serious adverse events, and local and systemic reactions included feeling feverish, chills, muscle ache, headache, and malaise. For a more detailed report of the trial results, click here.

COVID-19 Updates from CDC

As of July 17, 2020, the CDC has received reports of a total of 25,502,956 specimens tested for SARS-CoV-2, of which, 2,461,009 (9.6%) were positive.5

Levels of influenza-like illness (ILI) are low, but high for the time of year. Overall, the cumulative COVID-19-associated hospitalization rate is 113.6 per 100,000. Rates are highest among individuals aged 65 years and older (321.8 per 100,000) and those aged 50-64 years (171.8 per 100,000). Weekly hospitalization rates have increased over the last 2 weeks, which is the first time since April that increases have been observed over a multi-week period.

Percentages of deaths attributed to pneumonia, influenza, or COVID-19 decreased from 8.1% during week 27 to 6.4% during week 28 (ending July 11), which is the twelfth consecutive week in which a decrease in this percentage has been observed.

—Michael Potts

References:

  1. Pham TD, Huang C, Wirz OF, et al. SARS-CoV-2 RNAemia in a healthy blood donor 40 days after respiratory illness resolution. Published online July 17, 2020. Ann Intern Med. doi:10.7326/L20-0725
  2. The RECOVERY Collaborative Group. Dexamethasone in hospitalized patients with COVID-19 — preliminary report. Published online July 17, 2020. NEJM. doi:10.1056/NEJMoa2021436
  3. Huang YS, Vanlandingham DL, Bilyeu AN, et al. SARS-CoV-2 failure to infect or replicate in mosquitoes: an extreme challenge. Published online July 17, 2020. Nature. doi:10.1038/s41598-020-68882-7
  4. Folegatti PM, Ewer KJ, Aley PK, et al. Safety and immunogenicity of the ChAdOx1 nCoV-19 vaccine against SARS-CoV-2: a preliminary report of a phase 1/2, single-blind, randomised controlled trial. Published online July 20, 2020. Lancet. doi:/10.1016/S0140-6736(20)31604-4
  5. 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 July 17, 2020. Accessed July 20, 2020.