Respiratory viruses in rural Zambia before and during the COVID-19 pandemic.

OBJECTIVES: With the emergence of the COVID-19 pandemic, restrictions were implemented globally to control the virus. Data on respiratory pathogens in sub-Saharan Africa during the COVID-19 pandemic are scarce. This analysis was conducted to evaluate patterns of respiratory pathogens in rural Zambia before and during the first year of the pandemic. METHODS: Surveillance was established in December 2018 at Macha Hospital in southern Zambia. Patients with respiratory symptoms in the outpatient and inpatient clinics were recruited. Nasopharyngeal samples were collected and tested for respiratory pathogens. The prevalence of respiratory symptoms and pathogens was evaluated and compared in the first (December 10, 2018-December 9, 2019) and second (December 10, 2019-November 30, 2020) years of surveillance. RESULTS: Outpatient visits and admissions for respiratory illness significantly decreased from the first to second year, especially among children. SARS-CoV-2 was not detected from any participants in Year 2. Among outpatients and inpatients with respiratory symptoms, the prevalence of respiratory syncytial virus and influenza viruses decreased from the first to second year. In contrast, the prevalence of rhinovirus/enterovirus, metapneumovirus and parainfluenza virus increased. CONCLUSIONS: The epidemiology of respiratory viruses in rural Zambia changed during the first year of the COVID-19 pandemic, suggesting that public health interventions may have had an impact on the introduction and circulation of respiratory pathogens in this area.

Facility-based surveillance for influenza and respiratory syncytial virus in rural Zambia.

BACKGROUND: While southern Africa experiences among the highest mortality rates from respiratory infections, the burden of influenza and respiratory syncytial virus (RSV) in rural areas is poorly understood. METHODS: We implemented facility-based surveillance in Macha, Zambia. Outpatients and inpatients presenting with influenza-like illness (ILI) underwent testing for influenza A, influenza B, and RSV and were prospectively followed for 3 to 5 weeks to assess clinical course. Log-binomial models assessed correlates of infection and clinical severity. RESULTS: Between December 2018 and December 2019, 17% of all outpatients presented with ILI and 16% of inpatients were admitted with an acute respiratory complaint. Influenza viruses and RSV were detected in 17% and 11% of outpatient participants with ILI, and 23% and 16% of inpatient participants with ILI, respectively. Influenza (July-September) and RSV (January-April) prevalence peaks were temporally distinct. RSV (relative risk [RR]: 1.78; 95% confidence interval [CI] 1.51-2.11), but not influenza, infection was associated with severe disease among patients with ILI. Underweight patients with ILI were more likely to be infected with influenza A (prevalence ratio [PR]: 1.72; 95% CI 1.04-2.87) and to have severe influenza A infections (RR: 2.49; 95% CI 1.57-3.93). CONCLUSIONS: Populations in rural Zambia bear a sizeable burden of viral respiratory infections and severe disease. The epidemiology of infections in this rural area differs from that reported from urban areas in Zambia.

Respiratory viruses in rural Zambia during the second year of the COVID-19 pandemic.

Objectives: Limited data on respiratory infections are available from sub-Saharan Africa during the COVID-19 pandemic. The objective of this study was to evaluate the burden of respiratory viruses in rural Zambia from 2019-2021. Methods: Surveillance was initiated at Macha Hospital in Zambia in December 2018. Each week, patients with respiratory symptoms were enrolled from the outpatient clinic. Nasopharyngeal samples were collected and tested for respiratory pathogens. The prevalence of respiratory symptoms and viruses in 2021 was compared to results from 2019 and 2020. Results: After seeing few cases of influenza virus and respiratory syncytial virus in 2020, a return to prepandemic levels was observed in 2021. Rhinovirus/enterovirus, parainfluenza virus 1-4, and adenovirus circulated from 2019 to 2021, while human metapneumovirus and human coronaviruses (HKU1, 229E, OC43, and NL63 subtypes) were observed sporadically. SARS-CoV-2 was observed consistently in 2021 after being first identified in December 2020. The proportion of participants with co-infections in 2021 (11.6%) was significantly higher than in 2019 (6.9%) or 2020 (7.7%). Conclusion: Declines in influenza virus and respiratory syncytial virus were reversed once public health measures were lifted. Respiratory viruses contributed to a significant burden of respiratory infections in 2021. This study provides important information about respiratory viruses in this changing context and underrepresented region.

Uptake of public health measures and vaccine acceptance during the COVID-19 pandemic in rural Zambia.

Vaccines are effective tools to prevent COVID-19-related morbidity. However, coverage is low throughout sub-Saharan Africa. Uptake of public health measures, perceptions of COVID-19 illness and vaccines, and intention to vaccinate were evaluated in 2021-2022 in rural Zambia. Adherence to public health measures, perceptions of COVID-19 risk and severity, and vaccine acceptance increased significantly over time, particularly in December 2021, coinciding with the fourth pandemic wave and relaunch of the national vaccine campaign. Vaccine acceptance was associated with perceptions of vaccine safety and effectiveness, but not disease severity. These findings highlight the importance of strong pandemic response and public communication for increased uptake of mitigatory measures, including vaccine acceptance.

Weight and height z-scores improve after initiating ART among HIV-infected children in rural Zambia: a cohort study.

BACKGROUND: Deficits in growth observed in HIV-infected children in resource-poor settings can be reversed with antiretroviral treatment (ART). However, many of the studies have been conducted in urban areas with older pediatric populations. This study was undertaken to evaluate growth patterns after ART initiation in a young pediatric population in rural Zambia with a high prevalence of undernutrition. METHODS: Between 2007 and 2009, 193 HIV-infected children were enrolled in a cohort study in Macha, Zambia. Children were evaluated every 3 months, at which time a questionnaire was administered, height and weight were measured, and blood specimens were collected. Weight- and height-for-age z-scores were constructed from WHO growth standards. All children receiving ART at enrollment or initiating ART during the study were included in this analysis. Linear mixed effects models were used to model trajectories of weight and height-for-age z-scores. RESULTS: A high proportion of study children were underweight (59%) and stunted (72%) at treatment initiation. Improvements in both weight- and height-for-age z-scores were observed, with weight-for-age z-scores increasing during the first 6 months of treatment and then stabilizing, and height-for-age z-scores increasing consistently over time. Trajectories of weight-for-age z-scores differed by underweight status at treatment initiation, with children who were underweight experiencing greater increases in z-scores in the first 6 months of treatment. Trajectories of height-for-age z-scores differed by age, with children older than 5 years of age experiencing smaller increases over time. CONCLUSIONS: Some of the effects of HIV on growth were reversed with ART initiation, although a high proportion of children remained underweight and stunted after two years of treatment. Partnerships between treatment and nutrition programs should be explored so that HIV-infected children can receive optimal nutritional support.

Respiratory pathogen diversity and co-infections in rural Zambia.

OBJECTIVES: The role of respiratory co-infections in modulating disease severity remains understudied in southern Africa, particularly in rural areas. This study was performed to characterize the spectrum of respiratory pathogens in rural southern Zambia and the prognostic impact of co-infections. METHODS: Respiratory specimens collected from inpatient and outpatient participants in a viral surveillance program in 2018-2019 were tested for selected viruses and atypical bacteria using the Xpert Xpress Flu/RSV assay and FilmArray Respiratory Panel EZ. Participants were followed for 3-5 weeks to assess their clinical course. Multivariable regression was used to examine the role of co-infections in influencing disease severity. RESULTS: A respiratory pathogen was detected in 63.2% of samples from 671 participants who presented with influenza-like illness. Common pathogens identified included influenza virus (18.2% of samples), respiratory syncytial virus (RSV) (11.8%), rhinovirus (26.4%), and coronavirus (6.0%). Overall, 6.4% of participants were co-infected with multiple respiratory pathogens. Compared to mono-infections, co-infections were found not to be associated with severe clinical illness either overall (relative risk (RR) 0.72, 95% confidence interval (CI) 0.39-1.32) or specifically with influenza virus (RR 0.80, 95% CI 0.14-4.46) or RSV infections (RR 0.44, 95% CI 0.17-1.11). CONCLUSIONS: Respiratory infections in rural southern Zambia were associated with a wide range of viruses. Respiratory co-infections in this population were not associated with clinical severity.

Nosocomial Respiratory Infections in a Rural Zambian Hospital.

The burden of nosocomial respiratory infections in rural southern Africa is poorly understood. We established a surveillance program at a rural Zambian hospital to detect influenza-like illness (ILI) and respiratory infections among hospitalized patients and a cohort of healthcare workers (HCWs). Nasopharyngeal specimens from symptomatic patients and HCWs underwent broadly multiplexed molecular testing to detect viruses and atypical bacteria. During 1 year of surveillance, 15 patients (1.7% of admissions) developed ILI more than 48 hours after admission. Among 44 HCWs, 19 (43%) experienced at least one ILI episode, with a total of 31 ILI episodes detected. Respiratory viruses were detected in 45% of patient and 55% of HCW specimens. The cumulative incidence of influenza infection among HCWs over 1 year was 9%. Overall, respiratory viruses were commonly found among patients and HCWs in a rural Zambian hospital with limited infection control infrastructure.

HIV-infected children in rural Zambia achieve good immunologic and virologic outcomes two years after initiating antiretroviral therapy.

BACKGROUND: Many HIV-infected children in sub-Saharan Africa reside in rural areas, yet most research on treatment outcomes has been conducted in urban centers. Rural clinics and residents may face unique barriers to care and treatment. METHODS: A prospective cohort study of HIV-infected children was conducted between September 2007 and September 2010 at the rural HIV clinic in Macha, Zambia. HIV-infected children younger than 16 years of age at study enrollment who received antiretroviral therapy (ART) during the study were eligible. Treatment outcomes during the first two years of ART, including mortality, immunologic status, and virologic suppression, were assessed and risk factors for mortality and virologic suppression were evaluated. RESULTS: A total of 69 children entered the study receiving ART and 198 initiated ART after study enrollment. The cumulative probabilities of death among children starting ART after study enrollment were 9.0% and 14.4% at 6 and 24 months after ART initiation. Younger age, higher viral load, lower CD4+ T-cell percentage and lower weight-for-age z-scores at ART initiation were associated with higher risk of mortality. The mean CD4(+) T-cell percentage increased from 16.3% at treatment initiation to 29.3% and 35.0% at 6 and 24 months. The proportion of children with undetectable viral load increased to 88.5% and 77.8% at 6 and 24 months. Children with longer travel times (≥ 5 hours) and those taking nevirapine at ART initiation, as well as children who were non-adherent, were less likely to achieve virologic suppression after 6 months of ART. CONCLUSIONS: HIV-infected children receiving treatment in a rural clinic experienced sustained immunologic and virologic improvements. Children with longer travel times were less likely to achieve virologic suppression, supporting the need for decentralized models of ART delivery.