Age and sex distribution trends of SARS-CoV-2 infections: Insights from three epidemic waves in Puducherry, India

Introduction: This study analyzed the age and sex distribution of COVID-19 patients during the initial three COVID-19 waves in Puducherry, India, from August 2020 to March 2022, to understand the distribution of infection across different demographic groups. Methods: The disease surveillance program conducted at ICMR-Vector Control Research Centre processed 79,705 Throat Swab/Nasal Swab (TSNS) samples received from various institutions in Puducherry through the Integrated Disease Surveillance Program (IDSP). Real-time reverse-transcriptase-polymerase chain reaction (rRT-PCR) was performed following approved protocols. Results: Test positivity rates during the second (14.6%) and third waves (25.1%) were significantly higher than the first wave (11.4%). In the first wave, children (p < 0.001) and elderly individuals (p = 0.017) had a lower risk of testing positive than adults. However, in the second wave, elderly individuals had a 1.12 (95% CI: 1.03 – 1.23) times greater risk of contracting COVID-19 (p = 0.013). Children had a lower risk of testing positive across all waves (p < 0.001). A significant sex difference was noted only in the first wave, with males having a 1.27 (1.18-1.37) times greater chance of being COVID-19 positive. The mean age of female patients was significantly younger than male patients in the third wave (p = 0.008). The third wave showed an increasing trend of infection across all age groups and sexes, especially among younger individuals. Conclusions: The study highlights an increasing trend of infections across all age groups and sexes during the third wave. Micro-epidemiological analyses are crucial for developing targeted intervention strategies that address age and sex demographics effectively.