Respiratory syncytial virus genotypes circulating in urban Ghana: February to November 2006

Epidemiology and genetic diversity of respiratory syncytial virus in adults 50 years and older with acute respiratory infections in Accra, Ghana

BACKGROUND

Human respiratory syncytial virus (RSV) is responsible for lower respiratory tract infections, particularly posing a significant threat to infants, the elderly, and immunocompromised individuals. However, the disease burden is poorly understood in the adult population in Africa. This molecular study investigated the occurrence of RSV in adults 50 years and older and assessed the genetic variability of circulating RSV genotypes in patients with acute respiratory tract infection (ARI) in Accra, Ghana.

METHODS

From March to October 2023, patients who are ≥ 50 years of age with confirmed ARI cases were enrolled from three hospitals in Accra, Ghana. Nasopharyngeal specimens were collected and analyzed for RSV using real-time quantitative PCR. The second hypervariable region of RSV-positive samples was targeted for sequencing. Bioinformatics analysis was carried out to identify the predominant circulating genotypes and a phylogeny established between sequences from this study and other globally circulating RSV genotypes. Amino acids deduction analysis was performed to identify the genetic variability and evolution of the RSV genotypes identified.

RESULTS

A total of 212 patients were enrolled. RSV infection was confirmed in 11 (5.2%) participants. RSV infection was more prevalent among patients aged 65 years and older (8/11, 54.5%). Patients with underlying chronic diseases (18%) suffered severe medically attended RSV complications requiring intensive care and ventilation support. RSV disease was significantly associated with cough (p = 0.023). Phylogenetic and amino acid sequence analysis revealed RSV-B sequences clustered as BA; specifically, the globally prevailing BA9 genotype. No cases of RSV-A were identified. RSV/BA9 dominated the season from July to October 2023. Specific amino acid substitutions both outside and within the duplication region of the G gene were present, and presence of individual clusters and branches provided evidence of strains diversification and evolution.

CONCLUSION

This study provides the first baseline report of RSV disease occurrence among adults ≥ 50 years in Ghana. It reveals the genetic diversification of prevailing RSV/BA9 genotypes identified and addresses the need for continuous RSV surveillances and targeted interventions in this frail population.

Pathogens associated with hospitalization due to acute lower respiratory tract infections in children in rural Ghana: a case-control study

Respiratory infections are one of the most common causes of death among children under the age of five years. Data on prevalence and relevance of specific organisms in African children are still lacking. This case-control-study investigated prevalence and relevance of specific organisms in Ghanaian children admitted to hospital with symptoms of lower respiratory tract infection (LRTI). Pharyngeal swabs were taken and tested by PCR for 19 respiratory isolates. Adjusted odds ratios (aORs) were calculated to estimate associations between isolates and admission with LRTI. Population attributable fractions (PAFs) were calculated to assess the proportion of LRTI cases due to a particular pathogen. The study included 327 cases and 562 controls. We found associations between detection and admission for LRTI for influenza (aOR 98.6; 95% confidence interval (CI) 20.0-1789.6), respiratory syncytial virus (aOR 40.2; 95% CI 7.2-758.6), H. influenzae (aOR 4.1; 95% CI 2.2-7.9) and S. pneumoniae (aOR 2.4; 95% CI 1.7-3.4). PAFs ≥ 10% were observed for S. pneumoniae (30%; 95% CI 26-42), H. influenzae (10%; 95% CI 2-19) and influenza (10%; 95% CI 2-18). This study highlights the need for heightened surveillance and development of effective vaccines for respiratory pathogens other than SARS-CoV-2 in the future.

Epidemiology of Respiratory Syncytial Virus-Associated Acute Lower Respiratory Tract Infection among Hospitalized Under-5s in Northwestern Nigeria

Objective Globally, 33 million cases of respiratory syncytial virus (RSV) infections occur annually among under-fives (5s). Ninety-nine percent of deaths from RSV occur in low- and middle-income countries. Under-five pneumonia mortality in Nigeria was estimated at 140,520 in 2017, but RSV epidemiological data are scant due to poor awareness and limited testing. Vaccines for RSV are currently under development and RSV mortality data from this high mortality, low resource setting are essential to maximizing the potential benefit of vaccination as well as promoting vaccine uptake. This study aimed to describe the epidemiology of RSV-associated acute lower respiratory tract infection (ALRTI) in children younger than 5 years in Zaria, Northwestern Nigeria.

Methods A prospective cohort study was conducted among children aged 1 month to 5 years who were hospitalized with ALRTI in the Emergency Pediatric Unit of a tertiary hospital in Zaria from November 2018 to October 2019. Naso-pharyngeal swabs were obtained for RSV testing using a point-of-care immunoassay technique.

Results Thirty-three percent (35/106) of the children had RSV-related ALRTI. The median age of RSV-positive cases was 8 months (IQR 3–14). Two-thirds of children (68.6%, 24/35) were below 12 months. The RSV mortality rate was 5.7% (2/35). RSV occurred in 10 months of the year with peaks in March and July.

Conclusion A third of admitted children with ALRTI were positive for RSV. Therefore RSV significantly contributes to childhood pneumonia and the dual seasonal peak observed in our study may have implications for vaccine implementation.

Molecular epidemiological surveillance of viral agents of acute lower respiratory tract infections in children in Accra, Ghana

BACKGROUND

Acute lower respiratory tract infection (ALRTI) in children under 5 years is known to be predominantly caused by respiratory syncytial virus (RSV). In recent times, however, human metapneumovirus (HMPV) has also been implicated. This study sought to investigate and genotype respiratory syncytial virus and human metapneumovirus in children presenting with ALRTIs infection at the Princess Marie Louis Children's Hospital in Accra, Ghana.

METHODS

Children below 5 years who were clinically diagnosed of ALRTI and on admission at the study site were recruited between September 2015 and November 2016 for this study. Demographic data information was obtained by means of a standardized questionnaire; and relevant clinical information was obtained from medical records. Nasopharyngeal swabs were collected from 176 children recruited for the study. Ribonucleic acid was extracted from swabs and cDNA syntheses were performed by RT-PCR. RSV-positive amplicons were sequenced and analyzed for genotype assignment.

RESULTS

RSV and HMPV prevalence among the sampled subjects were 11.4 and 1.7% respectively. Of the RSV positives, 8/20 (40%) were RSV-A and 12/20 (60%) were RSV-B. The highest prevalence was observed in children less than 12 months old. Phylogenetic analysis of the second hypervariable region of the RSV G-gene revealed that all RSV group A viruses belonged to the "novel" ON1 genotype containing the 72-nucleotide duplication; and RSV group B viruses belong to the BA IX genotype.

CONCLUSION

RSV is frequently detected in children aged under 5 years admitted with ALRTI in Ghana. Continued surveillance of viral aetiological agents is warranted to elucidate the prevalence and transmission patterns of viral pathogens that cause respiratory tract infections among children. This will help inform appropriate intervention approaches.

Respiratory syncytial virus in severe lower respiratory infections in previously healthy young Ethiopian infants

BACKGROUND

Respiratory Syncytial Virus (RSV) is the commonest cause of acute lower respiratory infections (ALRI) in infants. However, the burden of RSV is unknown in Ethiopia. We aimed to determine the prevalence, seasonality and predictors of RSV infection in young infants with ALRI for the first time in Ethiopia.

METHODS

We performed RSV immuno-chromatographic assay from nasopharyngeal swabs of infants, 29 days to 6 months of age. We included the first 10 eligible infants in each month from June 2018 to May 2019 admitted in a tertiary pediatric center. Clinical, laboratory and imaging data were also collected, and chi-square test and regression were used to assess associated factors with RSV infection.

RESULTS

Among a total of 117 study children, 65% were male and mean age was 3 months. Bronchiolitis was the commonest diagnosis (49%). RSV was isolated from 26 subjects (22.2%) of all ALRI, 37% of bronchiolitis and 11% of pneumonia patients. Although RSV infection occurred year round, highest rate extended from June to November. No clinical or laboratory parameter predicted RSV infection and only rainy season (Adjusted Odds Ratio (AOR) 10.46 [95%. C.I. 1.95, 56.18]) was independent predictor of RSV infection.

CONCLUSIONS

RSV was isolated in a fifth of young infants with severe ALRI, mostly in the rainy season. Diagnosis of RSV infection in our setting require specific tests as no clinical parameter predicted RSV infection. Since RSV caused less than a quarter of ALRI in our setting, the other causes should be looked for in future studies.

Prevalence of human respiratory syncytial virus infection in people with acute respiratory tract infections in Africa: A systematic review and meta-analysis

AIM

The epidemiology of human respiratory syncytial virus (HRSV) infection has not yet been systematically investigated in Africa. This systematic review and meta-analysis are to estimate the prevalence of HRSV infections in people with acute respiratory tract infections (ARTI) in Africa.

METHOD

We searched PubMed, EMBASE, Africa Journal Online, and Global Index Medicus to identify observational studies published from January 1, 2000, to August 1, 2017. We used a random-effects model to estimate the prevalence across studies. Heterogeneity (I2 ) was assessed via the chi-square test on Cochran's Q statistic. Review registration: PROSPERO CRD42017076352.

RESULTS

A total of 67 studies (154 000 participants) were included. Sixty (90%), seven (10%), and no studies had low, moderate, and high risk of bias, respectively. The prevalence of HRSV infection varied widely (range 0.4%-60.4%). The pooled prevalence was 14.6% (95% CI 13.0-16.4, I2  = 98.8%). The prevalence was higher in children (18.5%; 95% CI 15.8-21.5) compared to adults (4.0%; 95% CI 2.2-6.1) and in people with severe respiratory tract infections (17.9%; 95% CI 15.8-20.1) compared to those with benign forms (9.4%; 95% CI 7.4-11.5); P-values <0.0001. The HRSV prevalence was not associated with sex, subregion in Africa, setting, altitude, latitude, longitude, and seasonality.

CONCLUSION

This study suggests a high prevalence of HRSV in people with ARTI in Africa, particularly among children and people with severe clinical form. All innovative strategies to curb the burden should first focus on children which present the highest HRSV-related burden.

Contemporaneous data on the prevalence of Human Respiratory Syncytial Virus infection in people with acute respiratory tract infections in Africa (2000-2017)

Availability of accurate data on the burden of the Human Respiratory Syncytial Virus (HRSV) can help to implement better strategies to curb this burden in Africa continent among people with acute respiratory tract infections (ARTI). We summarize here available contemporaneous data published from January 1, 2000 to August 31, 2017 on the prevalence of HSRV infection among people with ARTI in the continent.

The significance of human respiratory syncytial virus (HRSV) in children from Ghana with acute lower respiratory tract infection: A molecular epidemiological analysis, 2006 and 2013-2014

BACKGROUND

Acute lower respiratory tract infection (ALRI) is a leading cause of childhood morbidity and mortality in developing countries. Globally, human respiratory syncytial virus (HRSV) is the most common pathogen of ALRI in infants and children. However, age-stratified HRSV disease burden data are largely absent from Africa, which is a key gap in informing an evidence-based recommendation for the introduction of an HRSV vaccine by the WHO.

METHODS

This study investigated the presence of HRSV in respiratory specimens from 552 children <5 years old with ALRI from Accra, Ghana in 2006 and 2013-2014 by real-time PCR. Of HRSV-positive samples the second hypervariable region of the viral G protein gene was sequenced and analyzed for phylogeny, characteristic amino acid substitutions, and potential glycosylation patterns. Further, HRSV infections have been characterized by age, symptoms and timely occurrence.

RESULTS

HRSV was observed in 23% (127/552) of the children with ALRI, with the highest incidence in infants younger than one year (33%, 97/295, p = 0.013). Within the observed seasonal circulation time of HRSV from June (mid-wet season) to December (beginning of the dry season) the incidence of ALRI due to HRSV was as high as 46% (125/273). HRSV disease was significantly associated with (broncho-) pneumonia, bronchiolitis, LRTI, and difficulty in breathing. Phylogenetic characterization of HRSV strains from Ghana identified the circulation of the currently worldwide prevailing genotypes ON1 and BA9, and shows evidence of an independent molecular evolution of ON1 and BA9 strains in Ghana resulting in potentially new subgenotypes within ON1 and BA9, provisionally named ON1.5, ON1.6, and BA9-IV.

CONCLUSION

This study addresses important knowledge gaps in the forefront of introducing the HRSV vaccine by providing information on the molecular evolution and incidence of HRSV in Accra (Ghana, Africa).