Infection, immunity, and surveillance of COVID-19

Dr Amitabh Suthar and Dr Christopher Dye give their perspective on infection, immunity and surveillance of COVID-19

Evaluation of approaches to strengthen civil registration and vital statistics systems: A systematic review and synthesis of policies in 25 countries.

BackgroundCivil registration and vital statistics (CRVS) systems play a key role in upholding human rights and generating data for health and good governance. They also can help monitor progress in achieving the United Nations Sustainable Development Goals. Although many countries have made substantial progress in strengthening their CRVS systems, most low- and middle-income countries still have underdeveloped systems. The objective of this systematic review is to identify national policies that can help countries strengthen their systems.Methods and findingsThe ABI/INFORM, Embase, JSTOR, PubMed, and WHO Index Medicus databases were systematically searched for policies to improve birth and/or death registration on 24 January 2017. Global stakeholders were also contacted for relevant grey literature. For the purposes of this review, policies were categorised as supply, demand, incentive, penalty, or combination (i.e., at least two of the preceding policy approaches). Quantitative results on changes in vital event registration rates were presented for individual comparative articles. Qualitative systematic review methodology, including meta-ethnography, was used for qualitative syntheses on operational considerations encompassing acceptability to recipients and staff, human resource requirements, information technology or infrastructure requirements, costs to the health system, unintended effects, facilitators, and barriers. This study is registered with PROSPERO, number CRD42018085768. Thirty-five articles documenting experience in implementing policies to improve birth and/or death registration were identified. Although 25 countries representing all global regions (Africa, the Americas, Southeast Asia, the Western Pacific, Europe, and the Eastern Mediterranean) were reflected, there were limited countries from the Eastern Mediterranean and Europe regions. Twenty-four articles reported policy effects on birth and/or death registration. Twenty-one of the 24 articles found that the change in registration rate after the policy was positive, with two supply and one penalty articles being the exceptions. The qualitative syntheses identified 15 operational considerations across all policy categories. Human and financial resource requirements were not quantified. The primary limitation of this systematic review was the threat of publication bias wherein many countries may not have documented their experience; this threat is most concerning for policies that had neutral or negative effects.ConclusionsOur systematic review suggests that combination policy approaches, consisting of at least a supply and demand component, were consistently associated with improved registration rates in different geographical contexts. Operational considerations should be interpreted based on health system, governance, and sociocultural context. More evaluations and research are needed from the Eastern Mediterranean and Europe regions. Further research and evaluation are also needed to estimate the human and financial resource requirements required for different policies

Accuracy of rapid point-of-care antigen-based diagnostics for SARS-CoV-2: An updated systematic review and meta-analysis with meta-regression analyzing influencing factors

Background Comprehensive: information about the accuracy of antigen rapid : diagnostic tests (Ag-RDTs) for Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) is essential to guide public health decision makers in choosing the best tests and testing policies. In August 2021, we published a systematic review and meta-analysis about the accuracy of Ag-RDTs. We now update this work and analyze the factors influencing test sensitivity in further detail. Methods and findings We registered the review on PROSPERO (registration number: CRD42020225140). We systematically searched preprint and peer-reviewed databases for publications evaluating the accuracy of Ag-RDTs for SARS-CoV-2 until August 31, 2021. Descriptive analyses of all studies were performed, and when more than 4 studies were available, a random-effects meta-analysis was used to estimate pooled sensitivity and specificity with reverse transcription polymerase chain reaction (RT-PCR) testing as a reference. To evaluate factors influencing test sensitivity, we performed 3 different analyses using multivariable mixed-effects meta-regression models. We included 194 studies with 221,878 Ag-RDTs performed. Overall, the pooled estimates of Ag-RDT sensitivity and specificity were 72.0% (95% confidence interval [CI] 69.8 to 74.2) and 98.9% (95% CI 98.6 to 99.1). When manufacturer instructions were followed, sensitivity increased to 76.3% (95% CI 73.7 to 78.7). Sensitivity was markedly better on samples with lower RT-PCR cycle threshold (Ct) values (97.9% [95% CI 96.9 to 98.9] and 90.6% [95% CI 88.3 to 93.0] for Ct-values 90%) when high viral loads are present. With viral load, as estimated by Ct-value, being the most influential factor on their sensitivity, they are especially useful to detect persons with high viral load who are most likely to transmit the virus. To further quantify the effects of other factors influencing test sensitivity, standardization of clinical accuracy studies and access to patient level Ct-values and duration of symptoms are needed