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Hu et al., China


The article from Hu and colleagues reported three mild cases of Covid-19-infected patients treated with anti-viral Oseltamivir in China. They observed that even after virus nucleic acid testing turned negative in the respiratory specimens, anal swabs from 2 of 3 cases remained positive for 6 and 12 days, respectively. In addition to tests in respiratory tract samples, they suggest that tests should be conducted in stools or anal swab specimens before making decisions to leave the isolation period. Virus discharged in stool could be a potential source of transmission, and some procedures, such as appropriate disposal of faeces, could attenuate the virus spread.

Research highlights

  1. Three case reports of mild cases of Covid-19-infected patients;
  2. Virus nucleic acid testing turned negative in the respiratory specimens from all patients up to around 2 weeks on illness;
  3. Even after nasopharyngeal swab specimens turned negative, viral nucleic acids persistently were detectable in anal swab specimens from 2 out of 3 cases (6 and 12 days, respectively);
  4. Clinical observational findings presume that Covid-19 could also infect cell lines from the gastrointestinal tract

Research Impact

Research impact of the article is linked to the attenuation of the Covid-19 transmission. In fact, the present paper provides observations that may be useful to determine precisely when recovered Covid-19 patients would be able to leave their isolation period. Besides tests from respiratory tract samples, additional tests for viral nucleic acids in faeces or anal swabs could be important to make sure that the recovered Covid-19 patients are not able to transmit the virus anymore. Moreover, this suggests that some measures, such as appropriate stool disposal, would be crucial strategies to prevent the virus spread.


Case study

Strengths and weaknesses of the paper


  1. Main point: low numbers of patients (n = 3);
  2. Just observational study (case report) and not mechanistic (transmission not tested or verified);
  3. Data describing clinical and laboratory features of Covid-19 patients are not consistent and accurate over the text (e.g, errors such as 14 days – abstract section- instead of 12 days in positive test for anal swab in case 1).


  1. Work performed with Covid-19-infected patients over the initial outbreak in China;
  2. Provide useful information about importance of anal swabs tests in affected patients.