Profile of COVID-19 cases during four waves of the pandemic from May 2020 to March 2022 in the Haut-Ogooué region in Gabon.

BACKGROUND

During the COVID-19 pandemic, many countries experienced successive waves marked by a substantial increase in cases. Across these waves, the characteristics of confirmed cases varied, particularly with respect to age, sex, and disease severity. Gabon, a country in Central African, experienced four successive pandemic waves between 2020 and 2022. In the Haut-Ogooué province, the first COVID-19 case was identified in early May 2020. This study aimed to describe the epidemiological patterns and profiles of COVID-19 cases across the first four waves of the pandemic, based on molecular diagnostic data collected between May 2020 and March 2022 in the Haut-Ogooué province of Gabon.

METHODS

All individuals presenting with influenza-like illness or respiratory symptoms who attended a healthcare facility within the study area were included. Additionally, samples were collected from contact cases, as well as from departing and returning travelers. Samples from employees resuming work after vacation were also incorporated. SARS-CoV-2 diagnosis was performed using real-time reverse transcription polymerase chain reaction (RT-PCR), targeting the E gene and the RNA-dependent RNA polymerase gene. Data analysis was conducted using StatView version 5.0. Pearson's Chi-square test and Fisher's exact test were applied to compare patient demographic data during the four pandemic waves.

RESULTS

The mean age of COVID-19 cases was 38.3 ± 14.2 years, which remained constant across the four pandemic waves. There was no significant difference between waves when comparing the proportion of infected men versus infected women, however, more than 50% of confirmed cases were male during the four waves (p < 0.0001). Individuals aged 25 to 54 years were the most affected across all periods. A high proportion of asymptomatic cases was consistently reported, ranging from 83.1% to 91.1% over the four waves (p < 0.0001).

CONCLUSIONS

The epidemiological profile of the four pandemic waves was similar, despite a decrease in positivity between the waves. The proportion of asymptomatic cases remained consistently high across all waves, as observed in many African countries. These findings provide important public health insights into the impact of COVID-19 on the population of Haut-Ogooué and Gabon.