A new publication in Scientific Reports, led by Dr Grant Mackenzie and Professor Beate Kampmann from the Medical Research Council Unit The Gambia at the London School of Hygiene and Tropical Medicine, provides the necessary background information to determine if the introduction of vaccines against Respiratory Syncytial Virus (RSV) could be beneficial in The Gambia.
RSV causes respiratory tract infections in all parts of the world. These infections can be very severe, leading to deaths in young children, especially those with lung conditions and/or born prematurely.
Representative data from sub-Saharan Africa are few, and in order to address the ongoing burden of virus-associated Acute Lower Respiratory Infection (ALRI), and to develop evidence-based vaccination strategies, additional data are needed from low-income settings. Prior to introducing any vaccine, the disease burden needs to be clarified, and this publication provides data on the seasonality and prevalence of important respiratory viruses in The Gambia.
The team conducted monthly population-based surveys in rural Gambia from February to December 2015. Standardized criteria were used to identify and examine children with possible ALRI, who provided nose and throat samples. In addition, stored specimens from 50 children aged 2-23 months, who had previously been enrolled in pneumonia surveillance activities in Basse, were randomly selected to test for respiratory syncytial, parainfluenza (PIV) and influenza viruses.
From the 2385 children with possible ALRI enrolled, 519 samples were randomly selected to look for viral pathogens; over 50% of these samples had at least one virus present. To identify the strains of virus infecting the children, the team partnered with Dr Adam Meijer, Virologist at the National Institute for Public Health and the Environment in The Netherlands. Multiple strains of RSV and influenza viruses were found throughout the year, which contrasts with many other countries where the RSV season is more restricted. RSV was associated with eight times the number of ALRI cases compared to other respiratory viruses.
Dr. Mackenzie from the Disease Control and Elimination Theme at the MRCG at LSHTM, who also leads pneumococcal surveillance in Basse and made available the samples from previous pneumonia studies said: “We are pleased to close a data gap on the origin and seasonality of respiratory disease in children presenting with acute lower respiratory infection, and to gather much more detailed information about circulating strains”.
Dr. Adam Meijer said: “Data on the increased circulation of different influenza viruses twice a year in The Gambia provides important information for decision makers when it comes to The Gambia implementing influenza vaccination and making the choice when to use the northern hemisphere or the southern hemisphere vaccine composition”.
Professor Kampmann, Theme Leader for Vaccines & Immunity at the MRCG at LSHTM and senior investigator of the study said: “As our data confirm, an effective RSV vaccination strategy could have a major impact on the burden of ALRI in The Gambia. Promising candidates of such vaccines are now emerging, and we look forward to be involved in their evaluation.”
This work was supported by grants from the Bill & Melinda Gates Foundation, the UK Medical Research Council (MRC) and UK Department for International Development (DFID), the European and Developing Country Clinical Trial Program 2 (EDCTP2), the Dutch Ministry of Health, Welfare and Sport, and the Vaccines & Immunity theme at MRCG at LSHTM.