Mpox outbreak in an Amazonian state - 2022-2024 - Sexual transmission, HIV coinfection, and challenges for health equity in the Brazilian Amazon

Sep 27, 2026

Mpox in Brazil’s Northern Region expanded between 2022 and 2024, and an epidemiological description focused on sexual transmission, coinfections, and health equity challenges. A descriptive, retrospective study used secondary data from FVS to analyze sociodemographic, behavioral, and clinical variables. Among 1,128 reported cases, most were concentrated in the capital, with shifting incidence by year. Sexual transmission dominated, while HIV and other STI coinfections were frequent.

LanguageEnglish

CategoryHealthcare

FormatPDF

Pages2

Reading Time5 min

AccessFree to download

Introduction/Objective

Methods

Results

Conclusion

Keywords

contaminated water or food and/or intimate contact with an infected individual. The infectious period usually begins one to two weeks before symptom onset, when cases are still asymptomatic, increasing transmission and complicating HA control. It is commonly considered a sexually transmitted infection, particularly among men who have sex with men (MSM) . During sexual intercourse, contamination may occur through oral-anal, digital-anal, and genital-oral contact with an infected partner. In September 2024, after identifying an increase in hospitalized HA cases from the private sector that had not been reported, the municipality intensiﬁed surveillance, characterizing an outbreak starting in December 2023 and initiating an investigation to deﬁne the epidemiological proﬁle of cases and identify risk factors associated with increased HA detection. Methods: Identiﬁcation of additional unreported cases through systematic review of reactive anti-HAV IgM tests from private laboratories and the municipal laboratory. A case-control study was conducted, complemented by descriptive analysis of hospitalized cases, in partnership with CIEVSMG and the Ministry of Health. Results: Between December 2023 and May 2025, 355 HA cases were identiﬁed, 75% of them male, 83% aged 20 􀀕44 years, 10.5% HIV-positive, and 12.1% users of pre-exposure prophylaxis (PrEP) . In the case-control study, bivariate analysis indicated the following risk factors for HA: MSM, oral-anal sex, anal sex, water treated by household ﬁlters, consumption of food from street vendors, and consumption of frozen fruits. In multivariate analysis using hierarchical logistic regression, oral-anal sex remained independently associated with hepatitis A (Crude OR 4.29; 95% CI [1.16 􀀕15.84]; P = 0.034) (Adjusted OR 5.45; 95% CI [1.39􀀕21.28]; P = 0.015) . Conclusion: The ﬁndings demonstrate the sexual nature of the HA outbreak in the municipality. Among the implemented control measures, hepatitis A vaccination was expanded starting April 16th, 2025, to PrEP users, sexual and household contacts aged 11􀀕44 years of conﬁrmed HA cases. Keywords: Hepatitis virus, Case-control studies, Epidemiologic surveys. [https://doi.org/10.1016/j.bjid.2026.104897](https://doi.org/10.1016/j.bjid.2026.104897) aFundao de Vigila^ncia em Sade do Amazonas Dra. Rosemary Costa Pinto (FVS-RCP), Manaus, AM, Brazil b Universidade do Estado do Amazonas (UEA), Manas, AM, Brazil Introduction/Objective: Mpox, declared a Public Health Emergency of International Concern (PHEIC) in 2022, had its epicenter in the Northern Region of Brazil in an Amazonian state responsible for 64.9% of regional cases. This study aimed to describe the epidemiological proﬁle of the disease from 2022 to 2024, with emphasis on sexual transmission, coinfections, and challenges to health equity. Methods: Descriptive, retrospective study using secondary data from FVS. Sociodemographic (sex, age, race/skin color, education), behavioral (sexual orientation, risk practices), and clinical (symptoms, coinfections, outcomes) variables were analyzed. Descriptive analysis with absolute and relative frequencies was performed using Excel v.16.0 . Results: A total of 1,128 cases were reported (436 conﬁrmed by laboratory or clinical-epidemiological criteria), with 96.8% concentrated in the state capital and expansion to 7 inland municipalities in 2024 . There was a peak in 2022 (343 cases), a sharp decline in 2023 (10 cases), and an increase in 2024 (83 cases) . The predominant proﬁle consisted of men (95%), young adults aged 20􀀕39 (84%), self-identiﬁed as mixed race (72.9%), and with higher educational levels (83.1% highschool/university) . Sexual transmission was the main route (50.7%), with HIV coinfection in 53.2% and other STIs in 52.4% . Frequent symptoms included fever (79%), rash (64%), and genital/perianal lesions (47%) . Hospitalization occurred in only 4.3% . Conclusion: The outbreak reﬂects regional inequalities and overlappin

FAQs

What period and data source were used to study Mpox in the Amazonian state?

The study described the epidemiological profile from 2022 to 2024 using secondary data from FVS in a descriptive, retrospective design.

What were the main characteristics of Mpox cases reported during the study period?

Cases were predominantly male (95%) with most among young adults aged 20–39, concentrated largely in the state capital, and showing a peak in 2022 followed by a decline in 2023 and an increase in 2024.

Which transmission route and coinfections were most common?

Sexual transmission was the main route (50.7%). HIV coinfection occurred in 53.2%, and other STIs were present in 52.4%.

Sep 27, 2026

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