A cohort study in the Amazon Basin suggests long-COVID symptoms—reported in almost two thirds of COVID-19 patients—may be more likely in people who reported COVID reinfections over a 1-year period, but not in those with a history of tropical diseases, including dengue, malaria, and Zika. The study was published yesterday in The American Journal of Tropical Medicine and Hygiene.
The study was based on 12 months of follow-up of 1,371 patients with confined COVID-19 in Rio Branco, Acre, a municipality in the Brazilian Amazon Basin. Participants were followed up via telephone shortly after COVID-19 diagnosis and 12 months after. All participants reported a first infection from March 17 to August 26, 2020.
The average age of participants was 39.7 pears, and 50.7% were female. The average number of symptoms reported in the acute phase of infection with COVID was nine, and 32 (2.3%) were reinfected with COVID-19 at least 90 days after their first infection.
The authors noted that 877 (63.9%) participants reported symptoms related to COVID-19 at 12 months. Among those with long COVID, 43.5% said fatigue was their most significant symptom.
Almost 60% had history of tropical disease
Among all participants, 806 (58.8%) reported a history of tropical diseases, including dengue, malaria, Zika, chikungunya, leprosy, and visceral leishmaniasis.
Female sex, non-White race, number of acute-phase symptoms, body mass index, and reinfection were independent predictors of long COVID, but not previous infection with tropical diseases.
Dengue accounts for 71% of all previous tropical disease cases and was associated with greater symptoms in the acute phase of COVID-19.
"Although more than half of the individuals reported previous tropical infection, this characteristic was not associated with post-COVID-19 symptoms. Interestingly, Dengue accounts for 71% of all previous tropical disease cases and was associated with greater symptoms in the acute phase of COVID-19, but it was not associated with COVID-19 long-term symptoms," the authors wrote.