Global distribution of respiratory syncytial virus A and B infections: a systematic review

Abstract

Respiratory syncytial virus (RSV) is the main cause of severe respiratory infections in young children. The need for global epidemiologic data regarding RSV has been increasingly recognized. RSV A infections are reported more frequently than RSV B. Nonetheless, the temporal distribution of infections caused by both RSV groups has not been investigated globally. A systematic review was carried out regarding published studies on RSV A and B epidemiology, as well as RSV G gene ectodomain sequence data available at GenBank. A total of 76,668 [45,990 (60%) RSV A and 30,678 (40%) RSV B] positive samples from 83 countries were identified and included in the analysis. Genotype assignment was obtained in 5,340 RSV A and 2,518 RSV B sequences. Two patterns of RSV circulation were observed: continuous seasons with RSV A predominance and alternate predominance of RSV A and B. These patterns were observed in all regions, but the predominant RSV group seldom coincided in all continents during a given year or season. The most frequently identified RSV A genotype was NA1 (including ON1 viruses) (76.30%), and the most frequently identified RSV B genotype was BA (70.65%). Multiple genotypes circulated simultaneously throughout the evolutionary history of RSV, but genotype diversity decreased after the year 2000. The classification of RSV group and genotype is important for the development of vaccines, as well as to understand viral dynamics. This study displays the global and continental RSV circulation patterns from the first report of human RSV infection until the end of 2020.

Keywords: Respiratory syncytial virus; epidemiology; genotype; molecular epidemiology; respiratory viruses.

Figure 1.

Flow diagram of literature search. The total number of articles identified through the search strategy, the number of items excluded during the selection process (and reasons for exclusion), and the final number of articles included in the study are shown.

Figure 2.

Total number of RSV samples during each season/year included in 419 articles selected from the literature. Samples reported from a given season in the Northern Hemisphere [for example, 1980–1981] and samples identified in the subsequent calendar year in the Southern Hemisphere [for example, 1981]) are shown in the same season. Total samples reported in the graph: 76,668 (63,980 for the Northern Hemisphere and 12,688 for the Southern Hemisphere).

Figure 3.

Proportion of RSV A and RSV B detections during each Global season (Northern + Southern hemispheres, 76,668 samples) (A), season (Northern hemisphere, 63,980 samples, 83.4%) (B), and year (Southern hemisphere 12,688 samples, 16.5%) (C). The dashed line (white) indicates 50% to identify seasons (or years) in which RSV A or RSV B predominate.

Figure 4.

Number of RSV A (black line) and RSV B (gray line) detections during each Global season (Northern + Southern hemispheres, 76,668 samples) (A), season (Northern hemisphere, 63,980 samples) (B), or year (Southern hemisphere, 12,688 samples) (C).

Figure 5.

Proportion of RSV A and RSV B detections during each season or year in North America (A), South America (B), Europe (C), Africa (D), Asia (E), and Oceania (F). The dashed line (white) indicates 50% to identify seasons (or years) in which RSV A or RSV B predominate.

Figure 6.

Number of RSV A (black line) and RSV B (gray line) detections during each season/year in North America (A), South America (B), Europe(C), Africa (D), Asia (E), and Oceania (F). Of note, the Y axis scale varies in each continent, based on the maximum number of detections reported in a given season/year.

Figure 7.

Proportion of RSV genotypes during each year Globally (A), in the Northern hemisphere (B), in the Southern hemisphere (C). Genotype distribution was based on analysis of all RSV G gene ectodomain sequences available in GenBank with sample collection date up until 31 December 2020.

Figure 8.

Proportion of RSV genotypes during each year in North America (A), South America (B), Europe (C), Africa (D), Asia (E), and Oceania (F). Genotype distribution was based on analysis of all RSV G gene ectodomain sequences available in GenBank with sample collection date up until 31 December 2020.