Transmission risk of asymptomatic SARS-CoV-2 infection:a systematic review and meta-analysis

Background:Global evidence on the transmission of asymptomatic SARS-CoV-2 infection needs to be synthesized.Methods:A search of 4 electronic databases(PubMed,EMBASE,Cochrane Library,and Web of Science databases)as of January 24,2021 was performed.Preferred Reporting Items for Systematic Reviews and Meta-Analyses(PRISMA)guidelines were followed.Studies which reported the transmission rate among close contacts with asymptomatic SARS-CoV-2 cases were included,and transmission activities occurred were considered.The trans-mission rates were pooled by zero-inflated beta distribution.The risk ratios(RRs)were calculated using random-effects models.Results:Of 4923 records retrieved and reviewed,15 studies including 3917 close contacts with asymptomatic indexes were eligible.The pooled transmission rates were 1.79 per 100 person-days(or 1.79%,95%confidence interval[CI]0.41%-3.16%)by asymptomatic index,which is significantly lower than by presymptomatic(5.02%,95%CI 2.37%-7.66%;p<0.001),and by symptomatic(5.27%,95%CI 2.40%-8.15%;p<0.001).Subgroup anal-yses showed that the household transmission rate of asymptomatic index was(4.22%,95%CI 0.91%-7.52%),four times significantly higher than non-household transmission(1.03%,95%CI 0.73%-1.33%;p=0.03),and the asymptomatic transmission rate in China(1.82%,95%CI 0.11%-3.53%)was lower than in other countries(2.22%,95%CI 0.67%-3.77%;p=0.01).Conclusions:People with asymptomatic SARS-CoV-2 infection are at risk of transmitting the virus to their close contacts,particularly in household settings.The transmission potential of asymptomatic infection is lower than symptomatic and presymptomatic infections.This meta-analysis provides evidence for predict-ing the epidemic trend and promulgating vaccination and other control measures.Registered with PROS-PERO International Prospective Register of Systematic Reviews,CRD42021269446;https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=269446.

Treatment outcomes of HIV patients with hepatitis B and C virus co-infections in Southwest China:an observational cohort study

Background:Antiretroviral therapy(ART)has reduced mortality among people living with HIV(PLWH)in China,but co-infections of hepatitis B virus(HBV)and hepatitis C virus(HCV)may individually or jointly reduce the effect of ART.This study aimed to evaluate the impacts of HBV/HCV coinfections on treatment drop-out and mortality among PLWH on ART.Methods:A retrospective cohort study analysis of 58,239 people living with HIV(PLWH)who initiated antiretroviral therapy(ART)during 2010-2018 was conducted in Guangxi Province,China.Data were from the observational database of the National Free Antiretroviral Treatment Program.Cox proportional hazard models were fitted to evaluate the effects of baseline infection of HBV or HCV or both on death and treatment attrition among PLWH.Results:Our study showed high prevalence of HBV(11.5%),HCV(6.6%)and HBV-HCV(1.5%)co-infections.The overall mortality rate and treatment attrition rate was 2.95[95%confidence interval(CI):2.88-3.02]and 5.92(95%CI:5.82-6.01)per 100 person-years,respectively.Compared with HIV-only patients,HBV-co-infected patients had 42%higher mortality[adjusted hazard ratio(a HR)=1.42;95%CI 1.32-1.54],HCV-co-infected patients had 65%higher mortality(a HR=1.65;95%CI:1.47-1.86),and patients with both HCV and HBV co-infections had 123%higher mortality(a HR=2.23;95%CI:1.87-2.66).Conclusions:HBV and HCV coinfection may have an additive effect on increasing the risk of all-cause death among PLWH who are on ART.It is suggested that there is need for primary prevention and access to effective hepatitis treatment for PLWH.