China Reports Coronavirus Spread By Asymptomatic Cases

February 28th, 2020

By Gary Evans, Medical Writer

While the medical consensus is that the majority of cases of novel coronavirus COVID-19 are being spread by symptomatic patients, Chinese researchers recently reported some cases that suggest transmission from subclinical patients without the typical signs of fever, cough, and respiratory illness.

“[A] patient undergoing surgery in a hospital in Wuhan infected 14 healthcare workers even before fever onset,” the researchers reported.

Another case described in the paper was a patient who traveled from Shanghai to attend a meeting in Germany and was asymptomatic until the flight back to China. However, two of the patient's close contacts were infected, and another two people at the meeting acquired the coronavirus without close contact. In addition, the authors cite an asymptomatic 10-year-old boy who was found to have unusual lung images and markers of COVID-19 in his blood.

“These findings warrant aggressive measures (such as N95 masks, goggles, and protective gowns) to ensure the safety of healthcare workers during this COVID-19 outbreak," the authors emphasized.

Eye protection traditionally has been a weak link in personal protective equipment (PPE), with exposures to the unprotected eyes frequently cited in surveillance systems. In that regard, the Chinese researchers reported that a clinician who visited the epicenter at Wuhan City later developed conjunctivitis in the left eye and spiked a fever.

“The individual tested positive for COVID-19, suggesting its tropism to non-respiratory mucosal surfaces, thus limiting the effectiveness of face masks,” the authors noted. This latter case also underscores why healthcare workers must wear eye protection in the form of goggles and face shields for suspect or confirmed cases of the novel coronavirus.

“The eye protection is easy to forget about, but if people cough into your unprotected eyes, you have tear ducts that lead to the back of your throat,” said Michael Bell, MD, a medical epidemiologist at the Centers for Disease Control & Prevention (CDC). “It is something that is easily forgotten and we keep reminding people it is certainly a vulnerability.”

In response to a common question, Bell clarified at a CDC training session that safety glasses do not provide the sufficient eye protection for COVID-19. The CDC recommends goggles and a disposable face shield that covers the front and sides of the face.

“Unfortunately, safety glasses do not provide the wrap around extension that we would prefer,” Bell said. "You can imagine if they were to slide down your nose, your eyes would be somewhat exposed, so that would not be an option.”

As of Feb. 28, 2020, the CDC reported 62 cases of COVID-19 in the United States, including 44 repatriated from the Diamond Princess cruise ship. Many of these cases are thought to have recovered, but the CDC leaves them in the total case count. No one has died of COVID-19 in the United States, but one American died in Wuhan, China. Globally, as of February 27, the World Health Organization reported 82,294 cases, with 95% of them in China. There have been 2,747 deaths, 57 of them outside of China. At least 46 countries have reported one or more cases, with South Korea having the most outside of China at 1,766 COVID-19 cases.

For more on this topic, see the April 2020 issue of Hospital Employee Health.