SARS-CoV-2 infections among personnel providing home care services for the elderly in Stockholm, Sweden

Hassan, S. S.; Seigerud, A.; Arroyo Muhr, L. S.; Nordqvist-Kleppe, S.; Pin, E.; Manberg, A.; Hober, S.; Nilsson, P.; Engstrand, L.; Elfstrom, M.; Blomqvist, J.; Conneryd-Lundgren, K.; Dillner, J.

Background In March 2020, Stockholm, Sweden was hit by a severe outbreak of SARS-CoV-2. Four weeks later, a systematic study of testing for past or present infections among healthcare workers in the region was launched. Only a minority of COVID-19 related deaths occurred at hospitals and the study was therefore extended to employees in companies providing home care services for the elderly. Methods Five companies offered participation to 438 employees at work and 405 employees (92.5%) were enrolled. Serum samples were analyzed for IgG to SARS-CoV-2 and throat swabs were tested by for the SARS-CoV-2 virus by PCR. Results Among home care employees, 20.1% (81/403) were seropositive, about twice as many as in a simultaneously enrolled reference population (healthcare workers entirely without patient contact, n=3,671; 9.7% seropositivity). Only 13/379 employees (3.4%) had evidence of a current infection (PCR positivity). Among these, 5 were also seropositive (a sign of past infection or lingering infection after symptoms have resolved) and 3 were positive with only low amounts of virus. The combination of high amounts of virus and no antibodies, a characteristic for pre-symptomatic COVID-19, was thus present only in 5 employees (1.3%). Conclusions Personnel providing home service for the elderly appear to be a risk group for SARS-CoV-2 infection. Employees likely to be pre-symptomatic for COVID-19 can be readily identified by screening. Increased attention for protection of employees as well as of the elderly they serve is warranted.