Here we report a multi-center case series enrolled in 165 patients with confirmed SARS-CoV-2 infection in Fujian province, presenting the status of the COVID-19 outside Wuhan. Compared with the considerable proportion of critically ill cases and mortality in Wuhan [12, 13, 16], most patients in our study were non-severe with mild to moderate symptoms and older people were more likely to develop as severe or critical cases once infected.
A large proportion of patients had Wuhan exposure history due to the rapidly movement of population during traditional Chinese lunar new year. One third of infected patients were related to family clusters implying that avoiding transmission in family is urgent for control the pandemic. Moreover, reports has found the existence of asymptomatic patients  and covert coronavirus infections with mild or no symptoms could spread the virus , suggesting more studies on the asymptomatic cases are of great importance to understand and control this pandemic. In addition, the median incubation period was 7 days in Fujian province, longer than 5.2 days in one study found in early outbreak and 4 days in Zhejiang Province [17, 23], which maybe associate with the immunity of population or the size of our cohort.
Pathological findings revealed that count of peripheral CD4 and CD8 T cells were substantially decreased in COVID-19 with ARDS , suggesting lymphocyte count was a critical factor associated with disease severity and mortality. Our results demonstrated that many older patients was severe or critical cases and older age negatively correlated with lymphocyte count to some extent, which was consistent with SARS and MERS, implying that one of the potential risk factor of SARS-CoV-2 was older age[25–27]. The high probability of lymphopenia and hypoxemia of older patients may help illustrate why they were at high risk of severe form or even death.
In this study, most patients received antiviral drug lopinavir/ritonavir which had been reported to have the potential to treat SARS infections , however, the first trial of lopinavir/ritonavir in adults with Severe Covid-19 showed no benefits compared patients received standard care . Compared with the young, older patients accounting for most severe cases were more likely to be given corticosteroids and immunomodulators. Although corticosteroid treatment is not routinely recommended for COVID-19, pulmonary pathological results demonstrated that appropriate doses of steroids should be considered an important measure to prevent ARDS development for severe patients . Particularly, one important and special treatment was Chinese medicine whose effects required further exploration. By the end of our follow-up, the mortality rate was 0.6% far less than that in Wuhan [12, 13]. Only one critically ill patient with kidney transplantation history received ECMO treatment and eight patients developed ARDS among all cases, indicating that extensive quarantine and tracing policies taken by the government promoted early detection of infected people, which was meaningful for blocking the disease course timely.
Our results also showed age correlated positively with the period from exposure to the time when nucleic acid detection turned negative, that’s to say, the older, the time of viral shedding maybe longer, indirectly showing that older patients require more time to recover. One patient was tested negative nucleic acid results till the fifth detection, pointing out a small number of infected patients may be falsely discharged or excluded which was due to sampling methods, sensitivity of detection kit, and human error [19, 30].Therefore, it's necessary and cautious for suspected patients to be under quarantine and apply for further nucleic acid and specific antibody detection and follow up chest CT dynamically. Last but not least, for discharged patients, although they had improvements in radiological findings and no respiratory symptoms like cough, which decreased the transmission possibility, continuing quarantine at home and avoid close contact with others for another two weeks is essential as well.
The study has several limitations. Firstly, only 29 older patients confirmed with COVID-19 were enrolled in the study, so it may be not representative enough. Secondly, nearly half of patients are still hospitalized at the end of follow up, it is difficult to further figure out the true mortality and further assess risk factors for poor prognosis. Thirdly, we only did univariate analysis between age and some parameters without considering potential confounding factors, so further multivariate analysis maybe more persuasive.