The impact of COVID-19 on sick leave of the persons working in nursing homes in Spain. Usefulness of sick leave for the surveillance of the pandemic evolution

Background: The nursing homes represented high-risk settings for SARS-CoV-2 infection, both for residents and for the employees. The COVID-19 impact on long-term care facilities (LTCFs) is evaluated, measured through the employees sick leave (SL). The pandemic evolution in the general population aged between 16 and 65 years was analyzed together with the sick leave to assess the latter as a complementary indicator of the SARS-CoV-2 surveillance. Methods: A descriptive study of all sick leave processes due to COVID-19 recorded between February 15th 2020 and May 1st 2021 in nursing homes was carried out. The close contact sick leave/infection sick leave ratios, the 100,000 affiliated/occupied sick leave rates were computed and compared with the COVID-19 cases cumulative incidence notified to the National Network of epidemiological Surveillance (RENAVE). Results: 261.892 SL processes were recorded. The close contact sick leave/infection sick leave median ratio in nursing homes was 1.8 (Interquartile range, ICR: 1.1-3.3), with values lower than 1 at certain periods. The infection sick leaves were higher in number and ratio and prior to the cases recorded in RENAVE. The sick leave ratio ranged between 81.679/100.000 occupied in nursing homes with medical care and 4.895/100.000 in other residential facilities. Conclusions: The results confirmed the dramatic impact of COVID-19 in nursing homes and the inequalities characterizing this impact. They also confirmed the potential use of sick leave as an alternative source for epidemiological and public health surveillance, especially now, when the transition of the COVID-19 surveillance to a system not including universal individual surveillance is being discussed.