04/21/2020
Covid-19 Update - April 20, 2020
- More than 2.46 million cases in 210 countries worldwide
1.2 million in the past 13 days.
- Cases reported in the state of New York exceed the cases reported in any single country.
- As of April 16, deaths increased by 50% and cases by 352 in Wuhan, China - attributed this underreporting to a large surge of cases early in the outbreak, inadequate testing, and an overwhelmed healthcare system. Suppression of this data by health and government officials played a large role in inaccurate reporting.
- Similarly, in the U.S, a large increase in number in retrospective COVID-19–attributable deaths in New York State have been added to the national totals due to a decision by the U.S. CDC to include both confirmed and probable cases and deaths in its counts for all states moving forward. The additional deaths speak to large numbers of deaths at home and in nursing homes that were not tested for COVID-19.
- Wider spread testing criteria is being implemented but a negative test (did not show Covid-19) is no guarantee that one does not have Covid as there is up to a 25% false negative rate (negative test but actually has the virus). This reinforces the point that symptomatic people should still self-isolate if they feel ill.
- Development of accurate serological testing remains elusive as several companies race to develop verifiable results.
- Additional uncontrolled unpublished data from France in a further 1,061 patients treated for at least 3 days with hydroxychloroquine and azithromycin immediately after diagnosis showed good clinical and virological outcomes in 92% and a mortality of 0.5% overall. Several smaller studies (some controlled) with negative results for this drug combination have been reported. No conclusions can be made until large scale randomized trials are completed.
- COVID-19 vaccine development, which involves a new virus target and mostly novel vaccine technology platforms (DNA, RNA, viral vectors), are likely to increase the risks and costs associated with delivering a licensed vaccine and will require careful evaluation of effectiveness and safety at each step.
- Iceland has one of the highest COVID-19 infection rates (approximately 5,000 cases per million population). During the outbreak, persons with typical indications for testing as practiced in most countries (symptomatic returned travellers, contacts of confirmed cases) had a typical PCR positivity rate of 13.3%. During the peak of the outbreak (for 20 days in March), of 13,000 (6% of the population of Iceland) other asymptomatic persons screened by PCR from the general population, only 0.8% were positive. These data speak against the widespread occurrence of asymptomatic transmission by members of the population who are not cases or contacts themselves and supports a strategy of isolation of cases and contacts for outbreak control. Additional analysis confirms infection rates to be about 50% higher in women than in men.
- Many infectious disease experts believe that truly asymptomatic carriers are the exception, and presymptomatic and minimally symptomatic (sub-clinical) are better descriptions of what is really taking place. Once the worst of the pandemic is over, large scale antibody testing will tell how many previously infected asymptomatic persons were in the population but will not indicate how important those persons were in community transmission. Another important factor is that many minimally symptomatic people may not appear symptomatic to others.
- Airborne transmission has not been proven to occur in the community; this was restated by WHO on March 29.
- F***l transmission does not appear to occur despite the shedding of SARS-CoV-2 RNA in stool specimens for prolonged periods after illness resolution.
- In Chicago, details of a cluster of 16 eventual confirmed or probable cases (including 3 deaths) among non-household family members that resulted from 1 symptomatic index case have been published. The index case introduced infection at a family meal, a funeral, and a birthday party to begin onward transmission at each event. The cluster illustrates the importance of even small group gatherings in facilitating growth of COVID-19 when social distancing is not in place.
- No patient has had a positive viral culture more than 8 days after symptom onset. Shedding of viral RNA from saliva and nasopharyngeal secretions is at peak value on the day of symptom onset, remains high for approximately 6 days, declines significantly in the second week of illness, and usually ceases by day 14.
- Loss of the senses of smell and taste as a symptom of infection was found in 80% of cases in a multicenter European study, with higher frequency in women. In 12% of cases, anosmia/ageusia was the initial symptom.
- The presence of detectable RNA in secretions does not correlate with infectivity. A definitive study on this matter that has informed most recent guidelines, including those for return to work, was prepublished over a month ago and is now in Nature. No patient had a positive viral culture more than 8 days after symptom onset.
Thus, people with suspected or confirmed COVID should not return to work until after 7 days symptom onset AND over 72 hours free of fever and symptoms.
