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

Respiratory pathogens detected in specimens collected for COVID-19 surveillance in Zambia

Background

In Zambia, knowledge on the landscape of respiratory pathogens that circulated during the coronavirus disease 2019 (COVID-19) pandemic is limited.

Aim

This study investigated respiratory pathogens that circulated in Zambia during the COVID-19 pandemic.

Setting

Nasopharyngeal specimens collected between July 2020 and July 2021 for COVID-19 testing in hospitals, ports of entry, persons seeking certificates for international travel and in communities were used.

Methods

Proportional age-stratified sampling was used to select 128 specimens. The samples were screened for 33 other respiratory pathogens using the Fast Track Diagnostics multiplex molecular assay.

Results

Overall, 71.1% (n = 91/128) tested positive for at least one respiratory pathogen. Bacterial respiratory pathogens were more predominant (70.3%, n = 90/128) than viral (51.6%, n = 66/128). Staphylococcus aureus was the most prevalent, detected in 22.7% (n = 29/128). The prevalence of influenza was 13.3% (n = 17/128). Rhinovirus had a prevalence of 3.1% (n = 4/128), while it was 10.1% (n = 13/128) for adenovirus. Children, adolescents and the elderly accounted for most influenza-positive specimens, 76.5% (n = 13/17), while 100% (n = 3/3) of specimens positive for Moraxella catarrhalis were from children. All specimens testing positive for Haemophilus influenzae, 100% (n = 5/5) were from children and adolescents. Co-infections were detected in 57.1% (n = 52/91) of specimens testing positive for at least one pathogen.

Conclusion

Bacterial respiratory pathogens appeared to predominate circulation during the COVID-19 pandemic period.

Contribution

Bacterial respiratory pathogens should not be neglected when implementing public health mitigation measures.

Respiratory adenovirus infections in children: a focus on Africa

PURPOSE OF REVIEW

Lower respiratory tract infections (LRTIs) are an important cause of child morbidity and mortality globally, especially in children under the age of 5 years in Africa. Respiratory viruses, including human adenoviruses (HAdVs), are common causes of LRTIs in children. This review aims to shed light on the epidemiology, clinical manifestations, sequelae, and treatment options specific to adenovirus respiratory infections in African children.

RECENT FINDINGS

Recent evidence has challenged the perception that adenovirus is a negligible cause of LRTIs. Studies show HAdV emerging as the third most common viral pathogen in fatal pneumonias among under-5 children in low-income and middle-income African countries, contributing to 5.5% of all pneumonia deaths and ranking second in hospital-associated viral pneumonia deaths. Predominant HAdV serotypes associated with disease differ by country and region, and have changed over time. Risk factors for increased disease severity and long-term respiratory sequelae in previously healthy African children with HAdV LRTIs are not well established.

SUMMARY

Although respiratory viruses, including HAdV, are recognized contributors to LRTIs, the prevalence and impact of adenovirus infections have been under-recognized and understated. Available data suggests that African children, particularly those under 5 years old, are at risk of severe sequelae from respiratory HAdV infections. Long-term sequelae, including bronchiectasis and postinfectious bronchiolitis obliterans, further underscore the significant impact of HAdV infections. However, the scarcity of comprehensive data hampers our understanding of the extent of the impact of HAdV infections on child lung health in Africa. We recommend scaled-up HAdV surveillance, ensuring its consistent inclusion in population-level LRTI assessments, and expanded and equitable access to diagnostics for early recognition of African children at risk of developing chronic sequelae and death. Enhanced understanding of adenovirus epidemiology and clinical outcomes and the availability of therapeutic options are essential for informed public health strategies and clinical care.

Prevalence of Endemic Respiratory Viruses During the COVID-19 Pandemic in Urban and Rural Malawi

Background

We investigated endemic respiratory virus circulation patterns in Malawi, where no lockdown was imposed, during the COVID-19 pandemic.

Methods

Within a prospective household cohort in urban and rural Malawi, adult participants provided upper respiratory tract (URT) samples at 4 time points between February 2021 and April 2022. Polymerase chain reaction (PCR) was performed for SARS-CoV-2, influenza, and other endemic respiratory viruses.

Results

1626 URT samples from 945 participants in 542 households were included. Overall, 7.6% (n = 123) samples were PCR- positive for >1 respiratory virus; SARS-CoV-2 (4.4%) and rhinovirus (2.0%) were most common. No influenza A virus was detected. Influenza B and respiratory syncytial virus (RSV) were rare. Higher virus positivity were detected in the rural setting and at earlier time points. Coinfections were infrequent.

Conclusions

Endemic respiratory viruses circulated in the community in Malawi during the pandemic, though influenza and RSV were rarely detected. Distinct differences in virus positivity and demographics were observed between urban and rural cohorts.