ABSTRACT
Background: Knowing the prevalence of true asymptomatic coronavirus disease 2019 (COVID-19) cases is critical for designing mitigation measures against the pandemic. We aimed to synthesize all available research on asymptomatic cases and transmission rates. Methods: We searched PubMed, Embase, Cochrane COVID-19 trials, and Europe PMC for primary studies on asymptomatic prevalence in which (1) the sample frame includes at-risk populations, and;(2) follow-up was sufficient to identify pre-symptomatic cases. Meta-analysis used fixed-effects and random-effects models. We assessed risk of bias by combination of questions adapted from risk of bias tools for prevalence and diagnostic accuracy studies. Results: We screened 2,454 articles and included 13 low risk-of-bias studies from seven countries that tested 21,708 at-risk people, of which 663 were positive and 111 asymptomatic. Diagnosis in all studies was confirmed using a real-time reverse transcriptase–polymerase chain reaction test. The asymptomatic proportion ranged from 4% to 41%. Meta-analysis (fixed effects) found that the proportion of asymptomatic cases was 17% (95% CI 14% to 20%) overall and higher in aged care (20%;95% CI 14% to 27%) than in non-aged care (16%;95% CI 13% to 20%). The relative risk (RR) of asymptomatic transmission was 42% lower than that for symptomatic transmission (combined RR 0.58;95% CI 0.34 to 0.99, p = 0.047). Conclusions: Our one-in-six estimate of the prevalence of asymptomatic COVID-19 cases and asymptomatic transmission rates is lower than those of many highly publicized studies but still sufficient to warrant policy attention. Further robust epidemiological evidence is urgently needed, including in subpopulations such as children, to better understand how asymptomatic cases contribute to the pandemic.
ABSTRACT
Introduction: Implementation of WHO's multimodal (MM) strategy is essential for strengthening infection prevention and control programme (IPC) in a country. Objectives: To share the experience of Turkey about the strengthening infection prevention and control programme. Methods: In Turkey, structured IPC (infection control committees, training, surveillance, hand hygiene activities) has been put into practice since 2006 by MoH. However, after 2018 MoH focused on IPC core components for strengthening IPC. Electronic surveillance was strengthened. Turkey signed the pledge of hand hygiene and Train the Trainers (TTT) programme was organised for standardized approach based on the WHO' MM Hand Hygiene Improvement Strategy. In TTT programme, 34 IPC professionals from 18 hospitals were trained for multimodal HH improvement strategy and a short TTT programme was organized with 32 participants in the largest teaching hospital in Turkey. After Covid-19 pandemic, videos about multimodal hand hygiene strategy were used for e-learning by MoH. To this e-learning programme, 1845 IPC professionals registered and 1287 of them completed. National Infection Control Committee was established in 2018 and National Infection Control Programme and Action Plan was introduced in 2019. The Hand Hygiene Self-Assessment Framework (HHSAF) was first used nationally in 2019 for the documentation of HH situation and also focus on the future plans and challenges. HHSAF was translated in Turkish to increase participation of facilities. Results: HHSAF was sent to 216 hospitals and 125 (58%) submitted their HHSAF. Of these hospitals, 92 (74%) were state hospital, 20 (16%) were university hospital and 13 (10%) were private hospital. Responses to HHSAF questions related to key indicators of the WHO improvement strategy implementation were shown in Figure 1. Conclusion: The survey shows that improvement was achieved on having alcohol-based handrubs available, undertaking staff training, evaluation and feedback and displaying posters on hand hygiene around their hospital. However, a dedicated budget in infection control and improvements in institutional safety climate are gaps that should be focused on. (Figure Presented).