Low grade evidence shows IgG and IgM antibody response correlates with neutralizingantibody titerand viral clearance, which is suggestive of protective humoral immunity inCOVID-19 patients with mild to moderate symptoms.
There is no available evidence with which to estimate the durability of this protective response. However, if the immune response to SARS-CoV-2 resembles that toward SARS-CoV, this protective humoral immunity may persist for several years.
Higher IgG antibody titersand a robustresponse were noted in severe to criticallyill patients and were associated with lower viral clearance and a worse clinical prognosis.
Low grade evidence suggests that convalescent plasma treatment may improve the clinical status of critically ill COVID-19 patients(one case series with only five patients enrolled).
Howell-Spooner, B. How well does the presence and level of antibodies predict the presence or absence of the disease? 2020 Apr 14; Document no.: LAB041401-01 ESR. In: COVID-19 Rapid Evidence Reviews [Internet]. SK: SK COVID Evidence Support Team, c2020. 20 p. (CEST evidence search report)
Moderate to strong grade evidence show the overall sensitivityrangeof IgM, IgG, and combined IgM/IgG are 48.1% to 94.1%, 64.7% to 100%, 83% to 100%, respectively.
IgM/IgG combined assay, with the posterior probability of 99.15%, has greater accuracyand sensitivity than a single IgM or IgG test.
The sensitivity of antibody tests is extremely low (~ 11.1%) in the first week following the onsetof symptoms but increasesrapidlyduring the second week.
IgG and IgM titers in patients with severe disease arehigher than those in the non-severe patients.
Antibody testsmay detect the presence of COVID-19 in asymptomatic individuals with negative rt-PCRresults.
Wang, H; Reeder, B; Howell-Spooner, B. How well does the presence and level of antibodies predict the presence or absence of the disease? 2020 Apr 15; Document no.: LAB041401 RR. In: COVID-19 Rapid Evidence Reviews [Internet]. SK: SK COVID Evidence Support Team, c2020. 9 p. (CEST rapid review report)
Duncan, V. What sampling method is most appropriate for population testing? 2020 Apr 23; Document no.: LAB042201-01 ESR. In: COVID-19 Rapid Evidence Reviews [Internet]. SK: SK COVID Evidence Support Team, c2020. 14 p. (CEST evidence search report)
Howell-Spooner, B. What frequency of repeat population screening will be required? 2020 Apr 23; Document no.: LAB042202-01 ESR. In: COVID-19 Rapid Evidence Reviews [Internet]. SK: SK COVID Evidence Support Team, c2020. 40 p. (CEST evidence search report)
For COVID-19 there are no published data to identify optimal population sampling methods, however, a population-based sample in which testing is performed for both rt-PCR and serology might be recommended. There are also opportunities to examine innovative sampling strategies being used in pilot studies underway in other jurisdictions.
Vanstone, J; Reeder, B; Duncan, V. What sampling method is most appropriate for population testing? 2020 Apr 23; Document no.: LAB042201 RR. In: COVID-19 Rapid Evidence Reviews [Internet]. SK: SK COVID Evidence Support Team, c2020. 5 p. (CEST rapid review report)
Low grade evidence suggests that SARS-CoV-2 may persist within a population and lead to recrudescent outbreaks in winter months which may include the re-infection of previously infected individuals.
· Population monitoring by means of repeated cross-sectional surveys and/or longitudinal cohort studies is strongly advised by WHO
Wang, H; Reeder, B; Howell-Spooner, B. What frequency of repeat population screening will be required? 2020 Apr 25; Document no.: LAB042202 RR. In: COVID19 Rapid Evidence Reviews [Internet]. SK: SK COVID Evidence Support Team, c2020.
4 p. (CEST rapid review report)
· A wide range of tests are available for detection of viral RNA as well as serological and immunoassays for antibodies developed due to exposure to SARS CoV-2 in infected persons. Despite the emerging research, information about clinical validity of tests is limited.
· Multiple factors affect test performance including the nature of the specific test, type of specimen and its quality, severity and duration of illness at the time of testing. These individual variations hamper assessment of diagnostic accuracy and suggest that a combination of tests on multiple types of specimens at serial time points might be needed to confirm a COVID 19 diagnosis.
· Point of care tests are desirable and needed to scale up testing in low resource settings; however, tests are of variable quality and more research is needed before they can be relied on for clinical decision making.
Notes
No search conducted by SHA librarians. Search Alerts set up.
Williams-Roberts, H; Waldener, C. What is the accuracy of diagnostic tests for COVID-19 detection? 2020 May 12; Document no.: EPM051201 RR. In: COVID-19 Rapid Evidence Reviews [Internet]. SK: SK COVID Evidence Support Team, c2020. (CEST rapid review report)
Young, C; Dalidowicz, M; Miller, L. What factors can be used to identify negative PCR tests that are ‘false negatives’? 2020 May 21; Document no.: EOC052101-01 ESR. In: COVID-19 Rapid Evidence Reviews [Internet]. SK: SK COVID Evidence Support Team, c2020. 42 p. (CEST evidence search report)
