Burden of Respiratory Syncytial Virus–Associated Acute Respiratory Infections During Pregnancy
Authors: Kenmoe Sebastien , Chu Helen Y , Dawood Fatimah S , Milucky Jennifer , Kittikraisak Wanitchaya , Matthewson Hamish , Kulkarni Durga , Suntarattiwong Piyarat , Frivold Collrane , Mohanty Sarita , Havers Fiona , Li You , Nair Harish ,   PROMISE Investigators, Aerssens Jeroen , Callendret Benoit , Ispas Gabriela , Ahani Bahar , Atwell Jessica , Begier Elizabeth , Turiga Monica , Htar Tin Tin , Bangert Mathieu , Kramer Rolf , Vernhes Charlotte , Beutels Philippe , Bont Louis , Campbell Harry , Nair Harish , Li You , Kenmoe Sebastien , Osei-Yeboah Richard , Wang Xin , Cohen Rachel , Dos Santos Gael , Joosten Philip , Last Theo , Kumar Veena , Machin Nuria , Nohynek Hanna , Openshaw Peter , Paget John , Pollard Andrew , Teirlinck Anne , Urchueguía-Fornes Arantxa , Mira-Iglesias Ainara , Orrico-Sánchez Alejandro , Díez-Domingo Javier , Klint Johannesen Caroline , Miller Mark , Mikolajczyk Rafael , Heikkinen Terho 
Published: October 2023

Abstract

Background
With the licensure of maternal respiratory syncytial virus (RSV) vaccines in Europe and the United States, data are needed to better characterize the burden of RSV-associated acute respiratory infections (ARI) in pregnancy. The current study aimed to determine among pregnant individuals the proportion of ARI testing positive for RSV and the RSV incidence rate, RSV-associated hospitalizations, deaths, and perinatal outcomes.

Methods
We conducted a systematic review, following PRISMA 2020 guidelines, using 5 databases (Medline, Embase, Global Health, Web of Science, and Global Index Medicus), and including additional unpublished data. Pregnant individuals with ARI who had respiratory samples tested for RSV were included. We used a random-effects meta-analysis to generate overall proportions and rate estimates across studies.

Results
Eleven studies with pregnant individuals recruited between 2010 and 2022 were identified, most of which recruited pregnant individuals in community, inpatient and outpatient settings. Among 8126 pregnant individuals, the proportion with ARI that tested positive for RSV ranged from 0.9% to 10.7%, with a meta-estimate of 3.4% (95% confidence interval [CI], 1.9%–54%). The pooled incidence rate of RSV among pregnant individuals was 26.0 (95% CI, 15.8–36.2) per 1000 person-years. RSV hospitalization rates reported in 2 studies were 2.4 and 3.0 per 1000 person-years. In 5 studies that ascertained RSV-associated deaths among 4708 pregnant individuals, no deaths were reported. Three studies comparing RSV-positive and RSV-negative pregnant individuals found no difference in the odds of miscarriage, stillbirth, low birth weight, and small size for gestational age. RSV-positive pregnant individuals had higher odds of preterm delivery (odds ratio, 3.6 [95% CI, 1.3–10.3]).

Conclusions
Data on RSV-associated hospitalization rates are limited, but available estimates are lower than those reported in older adults and young children. As countries debate whether to include RSV vaccines in maternal vaccination programs, which are primarily intended to protect infants, this information could be useful in shaping vaccine policy decisions.