Unpacking the Pox: A Systematic Review of Chickenpox in Pakistan

Background: Chickenpox, caused by the varicella-zoster virus (VZV), remains an underreported and understudied public health concern in Pakistan, especially in the wake of recent outbreaks and the emergence of novel genotypes. Despite global efforts toward varicella control, Pakistan lacks comprehensive data on epidemiological trends, diagnostic practices, and viral strain diversity, hindering effective disease management and vaccination strategies. Objective: This systematic review aimed to evaluate the epidemiological patterns, clinical characteristics, diagnostic approaches, and molecular strain variations of chickenpox in Pakistan from 2004 to 2025, with a focus on identifying diagnostic gaps and implications of emerging genotypes for public health and vaccine planning. Methods: A systematic review was conducted following PRISMA guidelines. A total of eight eligible observational and cross-sectional studies were selected from an initial pool of 18 records after applying defined inclusion and exclusion criteria. Studies were retrieved from databases such as PubMed, PakMediNet, and Google Scholar, focusing on English-language articles related to chickenpox in Pakistan. Diagnostic methods included clinical evaluation, ELISA, complement fixation tests, and PCR. The primary outcomes assessed were complication prevalence, strain identification, and diagnostic accuracy. Ethical considerations followed the Helsinki Declaration where applicable. Descriptive statistics and comparative analyses were extracted; SPSS software was noted as the primary tool in eligible studies. Results: Key findings included 58.8% VZV positivity via complement fixation tests in Punjab, 30% thrombocytopenia prevalence in Khyber Pakhtunkhwa, and the first-time identification of the M4 genotype in 66.7% of outbreak cases in Islamabad and Punjab post-COVID-19. The mean pediatric age was 5.3 years with seasonal clustering, while adults aged 15–50 exhibited more severe complications including ARDS (0.078%). PCR proved to be a superior diagnostic method, and acyclovir treatment showed improved outcomes in severe cases. Conclusion: Chickenpox in Pakistan exhibits significant regional and demographic disparities, with emerging genotypes such as M4 posing challenges for existing diagnostic and vaccination strategies. Enhanced genomic surveillance, standardization of diagnostic protocols, and selective immunization programs are essential for reducing morbidity and controlling future outbreaks, especially among high-risk groups.