Household COVID-19 secondary attack rate and associated determinants in Pakistan; A retrospective cohort study.

BACKGROUND: COVID-19 household transmissibility remains unclear in Pakistan. To understand the dynamics of Severe Acute Respiratory Syndrome Coronavirus disease epidemiology, this study estimated Secondary Attack Rate (SAR) among household and close contacts of index cases in Pakistan using a statistical transmission model. METHODOLOGY: A retrospective cohort study was conducted using an inclusive contact tracing dataset from the provinces of Punjab and Khyber-Pakhtunkhwa to estimate SAR. We considered the probability of an infected person transmitting the infection to close contacts regardless of residential addresses. This means that close contacts were identified irrespective of their relationship with the index case. We assessed demographic determinants of COVID-19 infectivity and transmissibility. For this purpose based on evolving evidence, and as CDC recommends fully vaccinated people get tested 5-7 days after close contact with a person with suspected or confirmed COVID-19. Therefore we followed the same procedure in the close contacts for secondary infection. FINDINGS: During the study period from 15th May 2020 to 15th Jan 2021, a total of 339 (33.9%) index cases were studied from 1000 cases initially notified. Among close contact groups (n = 739), households were identified with an assumed mean incubation period of 8.2+4.3 days and a maximum incubation period of 15 days. SAR estimated here is among the household contacts. 117 secondary cases from 739 household contacts, with SAR 11.1% (95% CI 9.0-13.6). All together (240) SAR achieved was 32.48% (95% CI; 29.12-37.87) for symptomatic and confirmed cases. The potential risk factors for SAR identified here included; old age group (>45 years of age), male (gender), household members >5, and residency in urban areas and for index cases high age group. Overall local reproductive number (R) based on the observed household contact frequencies for index/primary cases was 0.9 (95% CI 0.47-1.21) in Khyber Pakhtunkhwa and 1.3 (95% CI 0.73-1.56) in Punjab. CONCLUSIONS: SAR estimated here was high especially in the second phase of the COVID-19 pandemic in Pakistan. The results highlight the need to adopt rigorous preventive measures to cut the chain of viral transmission and prevent another wave of COVID-19.

Molecular epidemiology and genotype distribution of hepatitis C in Pakistan; a multicenter cross-sectional study.

Pakistan has second highest burden of hepatitis C virus (HCV) infected patients in the World. Little is known about the molecular epidemiology and risk factors for prevailing HCV genotypes in Pakistan. Considering this a multicenter cross-sectional study was conducted at 23different viral hepatitis control and prevention centers. A total of 175,897 patients were registered and screened for HCV, out of which 73,180 (41.6%) were found positive on Architect screening test. The screened positive patients were sequentially tested on RT-PCR; where 41,241 (56.35%) were detected positive. Molecular characterization results showed genotype 3 (73.9%) as the most prevalent type, followed by genotype 1 (9.7%), and genotype 4 (0.3%) was isolated for the first time in Pakistan. On regression analysis; risk factors associated with genotype 3 and 1 included; age group of 30-50 years, rural residence, exposure to >10 injections, barber shaving, circumcision by barbers, and low literacy rate. Phylogenetic analysis based on genotypes identified in this study and sequences isolated from Pakistan in last 10 years demonstrated that genotype 3 and 1 are endemic locally in Punjab province. The high prevalence rate of HCV is a threat for a generalized epidemic and genetic recombination with such variability of genotypes identified here is an alarming condition. More focused attention and resources should be spent in awareness of the population to prevent the spread of HCV among high risk population.