Evolution of WHO COVID-19 mask guidelines amid intense demands for rapid advice.

During a health emergency, there is an urgent need to rapidly develop guidelines that meet minimum quality standards, as exemplified by the development of WHO guidelines on mask use in health care and community settings during the COVID-19 pandemic. Between January 2020 and October 2023, WHO developed 21 guideline updates on the use of masks as part of infection prevention and control (IPC) practices. Guideline developers had to deal with an ever-growing volume of evidence of variable quality.

Infection prevention and control risk factors for SARS-CoV-2 infection in health workers: a global, multi-centre, case-control study.

Background: Health workers were at higher risk for severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection during the coronavirus disease 2019 (COVID-19) pandemic due to occupational risk factors. This study aimed to characterize these risk factors as part of the World Health Organization (WHO) Unity Studies initiative.

Methods: This global, multi-centre, nested, case-control study was conducted in 121 healthcare facilities in 21 countries.

Risk factors for SARS-CoV-2 infection among health workers in India: a case control study.

Background: COVID-19 was declared as a Public Health Emergency of International Concern on 30th January 2020. Compared to the general population, healthcare workers and their families have been identified to be at a higher risk of getting infected with COVID-19. Therefore, it is crucial to understand the risk factors responsible for the transmission of SARS-CoV-2 infection among health workers in different hospital settings and to describe the range of clinical presentations of SARS-CoV-2 infection among them.

Infection prevention and control risk factors in health workers infected with SARS-CoV-2 in Jordan: A case control study.

Background: Despite under-reporting, health workers (HWs) accounted for 2 to 30% of the reported COVID-19 cases worldwide. In line with data from other countries, Jordan recorded multiple case surges among HWs.

Methods: Based on the standardized WHO UNITY case-control study protocol on assessing risk factors for SARS-CoV-2 infection in HWs, HWs with confirmed COVID-19 were recruited as cases from eight hospitals in Jordan.

Early epidemiological investigations: World Health Organization UNITY protocols provide a standardized and timely international investigation framework during the COVID-19 pandemic.

Background: The declaration of Coronavirus disease 2019 (COVID-19) as a Public Health Emergency of International Concern (PHEIC) on 30 January 2020 required rapid implementation of early investigations to inform appropriate national and global public health actions.

Methods: The suite of existing pandemic preparedness generic epidemiological early investigation protocols was rapidly adapted for COVID-19, branded the 'UNITY studies' and promoted globally for the implementation of standardized and quality studies. Ten protocols were developed investigating household (HH) transmission, the first few cases (FFX), population seroprevalence (SEROPREV), health facilities transmission (n = 2), vaccine effectiveness (n = 2), pregnancy outcomes and transmission, school transmission, and surface contamination.