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).
COVID-19 is primarily transmitted by symptomatic patientsand presymptomatic individuals.·Moderate grade evidence estimates that approximately 20% of COVID-19 transmission may bedue to that from presymptomatic individuals.However, estimates range from 6.4% -47%.·Asymptomatic individuals and environmental contaminationappear to contributelessto disease transmission,with estimated proportionsof 6% and 10%, respectivelyfrom modelling studies
Wang, H; Reeder, B; Howell-Spooner, B; What proportion of disease transmission is due to asymptomatic, pre-symptomatic and symptomatic cases? 2020 May 8; Document no.: LAB040701v2 RR. In: COVID-19 Rapid Evidence Reviews [Internet]. SK: SK COVID Evidence Support Team, c2020. 12 p. (CEST rapid review report)
Howell-Spooner, B. What proportion of disease transmission is due to asymptomatic, pre-symptomatic and symptomatic cases? 2020 May 8; Document no.: LAB040701v2-01 ESR. In: COVID-19 Rapid Evidence Reviews [Internet]. SK: SK COVID Evidence Support Team, c2020. 25 p. (CEST evidence search report)
