Asymptomatic people spread COVID-19 in hospitals, the study warns

In the midst of the COVID-19 pandemic, entering the hospital seems like a situation, at least risky, due to the risks that a healthy person risks becoming infected with the new coronavirus (SARS-CoV-2). However, reality can be different and even reversed, depending on the circumstances. According to a study conducted by researchers from the Federal University of Sao Paulo (Unifesp), asymptomatic people can transmit the coronavirus to already weakened patients in hospitals and this risk is greatly underestimated.

In an article published in the magazine The International Journal of Infectious Diseases, Brazilian researchers have assessed the real risks of asymptomatic and apparently healthy COVID-19 patients of transmitting the coronavirus within hospitals, without knowing it. Furthermore, one of the conclusions of the study is that the protective measures currently adopted may be inadequate in daily practice.

Asymptomatic cases of COVID-19

On August 29, the researchers tested all visitors to the São Paulo hospital (HU / Unifesp) and found that 4% of these people (6 out of 150) had COVID-19 asymptomatically. In addition to the examination, all were evaluated for symptoms of infection, including fever [≥37,8 ° C], cough, anosmia, dysgeusia, dyspnoea, myalgia, headache and nasal discharge. According to the research team, the visitors were asymptomatic when they arrived at the hospital.

Of the six asymptomatic individuals identified by the RT-PCR test, one had tested positive 20 days earlier but had no symptoms at the time of the visit and considered himself healthy. Another visitor, with a positive outcome, developed symptoms the day after the visit and the other four showed no symptoms during the final evaluation 14 days after the test.

The number of asymptomatic people may seem small, but it is significant considering the weakening condition of many hospitalized patients. According to Dr. Nancy Bellei, an infectious disease specialist at Unifesp and coordinator of the study, only the use of masks in healthcare facilities can generate false confidence in reducing the risks of transmission.

“The study suggests that, in the most intense moments of the pandemic, the number of visits should be more controlled,” emphasizes the infectious specialist. On the other hand, the expert adds that “in the future, when new rapid tests are available, it will be possible to test visitors daily”.

Result of asymptomatic visits

Two of the six patients seen by a person with COVID-19, asymptomatically, subsequently tested positive for the infection. It is worth remembering that in the hospital in question, patients can receive only one visit during the day, that is, a single external contact. However, it is not possible to define whether the contamination exactly occurred through contact between visitors and inmates. This is because these people are instructed to wear masks and comply with protective measures. In any case, visits can potentially be contaminating.

For this reason, the researchers suggest that healthcare facilities may need to consider local infection rates and active visitor screening, as well as symptom screening, to protect patients from transmission within the hospital. “In summary, surveillance of asymptomatic visitors with rigorous implementation of protective measures, during visiting periods, may need to be included in infection control practices in order to reduce transmissions in health care facilities,” the researchers complete.

To read the full study, published in The International Journal of Infectious Diseases, click here.