Antibody Response After SARS-CoV-2 Infection and Implications for Immunity : A Rapid Living Review.

BACKGROUND: The clinical significance of the antibody response after SARS-CoV-2 infection remains unclear. PURPOSE: To synthesize evidence on the prevalence, levels, and durability of detectable antibodies after SARS-CoV-2 infection and whether antibodies to SARS-CoV-2 confer natural immunity. DATA SOURCES: MEDLINE (Ovid), Embase, CINAHL, Cochrane Central Register of Controlled Trials, ClinicalTrials.gov, World Health Organization global literature database, and Covid19reviews.org from 1 January through 15 December 2020, limited to peer-reviewed publications available in English. STUDY SELECTION: Primary studies characterizing the prevalence, levels, and duration of antibodies in adults with SARS-CoV-2 infection confirmed by reverse transcriptase polymerase chain reaction (RT-PCR); reinfection incidence; and unintended consequences of antibody testing. DATA EXTRACTION: Two investigators sequentially extracted study data and rated quality. DATA SYNTHESIS: Moderate-strength evidence suggests that most adults develop detectable levels of IgM and IgG antibodies after infection with SARS-CoV-2 and that IgG levels peak approximately 25 days after symptom onset and may remain detectable for at least 120 days. Moderate-strength evidence suggests that IgM levels peak at approximately 20 days and then decline. Low-strength evidence suggests that most adults generate neutralizing antibodies, which may persist for several months like IgG. Low-strength evidence also suggests that older age, greater disease severity, and presence of symptoms may be associated with higher antibody levels. Some adults do not develop antibodies after SARS-CoV-2 infection for reasons that are unclear. LIMITATIONS: Most studies were small and had methodological limitations; studies used immunoassays of variable accuracy. CONCLUSION: Most adults with SARS-CoV-2 infection confirmed by RT-PCR develop antibodies. Levels of IgM peak early in the disease course and then decline, whereas IgG peaks later and may remain detectable for at least 120 days. PRIMARY FUNDING SOURCE: Agency for Healthcare Research and Quality. (PROSPERO: CRD42020207098).

A prospective comparison of evidence synthesis search strategies developed with and without text-mining tools.

OBJECTIVE: We compared the process of developing searches with and without using text-mining tools (TMTs) for evidence synthesis products. STUDY DESIGN: This descriptive comparative analysis included seven systematic reviews, classified as simple or complex. Two librarians created MEDLINE strategies for each review, using either usual practice (UP) or TMTs. For each search we calculated sensitivity, number-needed-to-read (NNR) and time spent developing the search strategy. RESULTS: We found UP searches were more sensitive (UP 92% (95% CI, 85-99); TMT 84.9% (95% CI, 74.4-95.4)), with lower NNR (UP 83 (SD 34); TMT 90 (SD 68)). UP librarians spent an average of 12 h (SD 8) developing search strategies, compared to TMT librarians' 5 hours (SD 2). CONCLUSION: Across all reviews, TMT searches were less sensitive than UP searches, but confidence intervals overlapped. For simple SR topics, TMT searches were faster and slightly less sensitive than UP. For complex SR topics, TMT searches were faster and less sensitive than UP searches but identified unique eligible citations not found by the UP searches.

Advancing knowledge of rapid reviews: an analysis of results, conclusions and recommendations from published review articles examining rapid reviews.

BACKGROUND: Rapid review (RR) products are inherently appealing as they are intended to be less time-consuming and resource-intensive than traditional systematic reviews (SRs); however, there is concern about the rigor of methods and reliability of results. In 2013 to 2014, a workgroup comprising representatives from the Agency for Healthcare Research and Quality's Evidence-based Practice Center Program conducted a formal evaluation of RRs. This paper summarizes results, conclusions, and recommendations from published review articles examining RRs. METHODS: A systematic literature search was conducted and publications were screened independently by two reviewers. Twelve review articles about RRs were identified. One investigator extracted data about RR methods and how they compared with standard SRs. A narrative summary is presented. RESULTS: A cross-comparison of review articles revealed the following: 1) ambiguous definitions of RRs, 2) varying timeframes to complete RRs ranging from 1 to 12 months, 3) limited scope of RR questions, and 4) significant heterogeneity between RR methods. CONCLUSIONS: RR definitions, methods, and applications vary substantially. Published review articles suggest that RRs should not be viewed as a substitute for a standard SR, although they have unique value for decision-makers. Recommendations for RR producers include transparency of methods used and the development of reporting standards.