Nosocomial infection and spread of SARS-CoV-2 infection among hospital staff, patients and caregivers

BACKGROUND: There are difficulties in diagnosing nosocomial transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in hospital settings. Furthermore, mortality of cases of nosocomial infection (NI) with SARS-CoV-2 is higher than that of the general infected population. In the early stage of the pandemic in Taiwan, as patients were not tested for SARS-CoV-2 at admission, NIs often go undetected. Strictly applying the systematic polymerase chain reaction (PCR) screening, as a standard infection control measure was subsequently implemented to reduce NI incidence. However, evidence on risk factors for SARS-CoV-2 NIs among healthcare workers (HCWs) and caregivers is limited. AIM: To assess NI incidence of SARS-CoV-2 among hospital staff, hospitalized patients, and caregivers, and the transmission routes of clusters of infection. METHODS: This descriptive retrospective analysis at our hospital from May 15 to August 15, 2021 included data on 132 SARS-CoV-2 NIs cases among hospital staff, inpatients, and caregivers who previously tested negative but subsequently identified with a positive SARS-CoV-2 reverse transcriptase-PCR (RT-PCR) test results, or a hospital staff who tested positive following routine SARS-CoV-2 RT-PCR test. Chi-square tests were performed to compare the differences between hospital staff and private caregivers, and between clusters and sporadic infections. RESULTS: Overall, 9149 patients and 2005 hospital staff members underwent routine SARS-CoV-2 RT-PCR testing, resulting in 12 confirmed cluster and 23 sporadic infections. Among the index cases of the clusters, three (25%) cases were among hospital staff and nine (75%) cases were among other contacts. Among sporadic infections, 21 (91%) cases were among hospital staff and two (9%) cases were among other contacts (P < 0.001). There was an average of 8.08 infections per cluster. The secondary cases of cluster infection were inpatients (45%), hospital staff (30%), and caregivers (25%). Private caregivers constituted 27% and 4% of the clusters and sporadic infections, respectively (P = 0.024); 92.3% of them were infected in the clusters. The mortality rate was 0.0%. CONCLUSION: The incidence of SARS-CoV-2 infection was relatively high among private caregivers, indicating a need for infection control education in this group, such as social distancing, frequent hand-washing, and wearing PPE.