Corrigendum: Decreased influenza activity during the COVID-19 pandemic in Ghana, 2020.

[This corrects the article DOI: 10.3389/fpubh.2023.1290553.].

Decreased influenza activity during the COVID-19 pandemic in Ghana, 2020.

Introduction: The COVID-19 pandemic had a significant effect on influenza activity globally. In this study, we analyzed trends of influenza activity in 2020 during the COVID-19 pandemic in Ghana. Methods: This was a cross-sectional study using active prospective influenza surveillance data from 29 sentinel sites. At the sentinel sites, we enrolled patients presenting with symptoms based on the WHO case definition for influenza-like illness (ILI) and severe acute respiratory illness (SARI). Oro and nasopharyngeal swabs were collected from patients and tested for the presence of influenza viruses using specific primers and probes described by the US-CDC. The percentage of positivity for influenza between 2017-2019 and 2021 was compared to 2020. Using the test for proportions in STATA 17.0 we estimated the difference in influenza activities between two periods. Results and discussion: Influenza activity occurred in a single wave during the 2020 surveillance season into 2021, September 28 2020-March 7 2021 (week 40, 2020-week 9, 2021). Influenza activity in 2020 was significantly lower compared to previous years (2017- 2019, 2021). Influenza A (H3) was more commonly detected during the early part of the year (December 30, 2019-March 8, 2020), while influenza B Victoria was more commonly detected toward the end of the year (September 28-December 28). In Ghana, adherence to the community mitigation strategies introduced to reduce transmission of SARS-CoV-2, which affected the transmission of other infectious diseases, may have also impacted the transmission of influenza. To the best of our knowledge, this is the first study in Ghana to describe the effect of the COVID-19 pandemic on influenza activity. The continuation and strict adherence to the non-pharmaceutical interventions at the community level can help reduce influenza transmission in subsequent seasons.

Phylogenetic and genetic characterization of influenza A H9N2 viruses isolated from backyard poultry in selected farms in Ghana.

INTRODUCTION: Avian influenza viruses (AIV) cause significant economic losses to poultry farmers worldwide. These viruses have the ability to spread rapidly, infect entire poultry flocks, and can pose a threat to human health. The National Influenza Centre (NIC) at the Noguchi Memorial Institute for Medical Research in collaboration with the Ghana Armed forces (GAF) and the U.S. Naval Medical Research Unit No. 3, Ghana Detachment (NAMRU-3) performs biannual surveillance for influenza viruses among poultry at military barracks throughout Ghana. This study presents poultry surveillance data from the years 2017 to 2019. METHODOLOGY: Tracheal and cloacal swabs from sick and healthy poultry were collected from the backyards of GAF personnel living quarters and transported at 4°C to the NIC. Viral ribonucleic acid (RNA) was isolated and analyzed for the presence of influenza viruses using real-time polymerase chain reaction (PCR) assays. Viral nucleic acids extracted from influenza A-positive specimens were sequenced using universal influenza A-specific primers. RESULTS: Influenza A H9N2 virus was detected in 11 avian species out of 2000 samples tested. Phylogenetic analysis of viral haemagglutinin (HA) protein confirms the possibility of importation of viruses from North Africa and Burkina Faso. Although the detected viruses possess molecular markers of virulence and mammalian host adaptation, the HA cleavage site anlaysis confirmed low pathogenicity of the viruses. CONCLUSIONS: These findings confirm the ongoing spread of H9 viruses among poultry in Ghana. Poultry farmers need to be vigilant for sick birds and take the appropriate public health steps to limit the spread to other animals and spillover to humans.

Epidemiology of influenza in Ghana, 2011 to 2019.

Influenza virus is an important contributor to acute respiratory illnesses and is estimated to cause up to 650,000 respiratory deaths each year. Ghana recorded influenza viruses as far back as 1918 when the Spanish influenza pandemic led to the death of >100,000 people in a population of 4 million at the time. An outbreak of highly pathogenic avian influenza A(H5N1) among poultry in Ghana in 2007, led to the establishment of virological surveillance for influenza-like illness (ILI) by the Noguchi Memorial Institute for Medical Research (NMIMR). This surveillance system, supported by the U.S. Naval Medical Research Unit-No. 3 (NAMRU-3) and the Ghana Health Service (GHS), monitors circulating influenza strains and activity to better understand the epidemiology of influenza in Ghana. We present here the results of this surveillance system from 2011 to 2019. As part of the Integrated Disease Surveillance and Response (IDSR) system of the GHS under the Ministry of Health (MOH), oropharyngeal and nasopharyngeal swabs were collected from patients who met a modified World Health Organization (WHO) case definition for ILI or severe acute respiratory illness (SARI) through a sentinel surveillance system in the country. Samples were transported to the National Influenza Centre (NIC) at the NMIMR and tested for influenza virus using protocols defined by the United States Centers for Disease Control and Prevention (CDC). Selected isolates were sent to the WHO collaborating centre in the United Kingdom for further antigenic characterization. From 2011 to 2019, the NIC tested a total of 21,747 ILI samples and 3,429 SARI samples. Influenza positivity rates were highest in the 5-14 year old group for both ILI (20.8%) and SARI (23.8%). Compared to females, more males were seen at the health facilities for ILI and SARI symptoms with a statistically significant difference in influenza positive ILI (15% vs 13.2%, p <0.001). In terms of absolute numbers, more cases were seen at the health centres during the wet seasons (April to October) compared to the dry seasons (November to March) in Ghana. This study presents 9 years of surveillance data from outpatient and inpatient setting on influenza activity as well as the influenza A subtypes and B lineages that drive the activity. This presents useful information for influenza vaccine selection and administration. Ghana's unique influenza activity patterns also present a challenge in predicting when an outbreak could occur.