Effectiveness of Maternal Influenza Vaccination in Peru PRIME Cohort. (1st February 2023)

• Record Type: Journal Article
• Authors: Owusu, Daniel; Dawood, Fatimah S; Azziz-Baumgartner, Eduardo; Tinoco, Yeny; Soto, Giselle; Gonzalez, Oswaldo; Cabrera, Santiago; Florian, Richard; Llajaruna, Edwin; Hunt, Danielle Rentz; Wesley, Meredith G; Yau, Tat; Arriola, Carmen S
• Is Part Of: Open forum infectious diseases. Volume 10:Number 2(2023)
• Publication Date: 2023-02-01
• Subjects: influenza -- maternal vaccination -- Peru -- pregnant -- vaccine effectiveness; Communicable diseases -- Periodicals; Medical microbiology -- Periodicals; Infection -- Periodicals; 616.9
• DOI: 10.1093/ofid/ofad033
• Languages: English
• ISSNs: 2328-8957

Abstract

Abstract: Background: Few studies have examined influenza vaccine effectiveness (VE) among women during pregnancy in middle-income countries. We used data from a prospective cohort of women who were pregnant in Peru to estimate effectiveness of the 2018 Southern Hemisphere influenza vaccine. Methods: Women at <28 weeks gestation were enrolled from 4 tertiary level hospitals in Lima, Peru at the start of the 2018 influenza season and followed until the end of their pregnancies. Participants had mid-turbinate nasal swabs collected and tested for influenza by reverse-transcription polymerase chain reaction (RT-PCR) with onset of ≥1 of myalgia, cough, runny nose or nasal congestion, sore throat, or difficulty breathing. Time-varying Cox proportional hazard regression models were used to estimate the risk of RT-PCR-confirmed influenza infection after adjusting for inverse probability treatment weight. Results: We followed 1896 women for a median of 127 days (interquartile range [IQR], 86–174). Participants had a median age of 29 years (IQR, 24–34). Among the 1896 women, 49% were vaccinated with the 2018 influenza vaccine and 1039 (55%) developed influenza-like illness, 76 (7%) of whom had RT-PCR-confirmed influenza. Incidence rates of RT-PCR-confirmed influenza were 36.6 and 15.3 per 100 000 person-days among women who were unvaccinated and vaccinated, respectively. Adjusted influenza VE was 22% (95% confidence interval, −64.1% to 62.9%). Conclusions: Participants vaccinated against influenza had more than 50% lower incidence of RT-PCR-confirmed influenza illness. Although the VE estimated through propensity weight-adjusted time-varying Cox regression did not reach statistical significance, our findings provide additional evidence about the value of maternal influenza vaccination in middle-income countries. Abstract : Incidence of RT-PCR-confirmed influenza illness was twice as high in participants who were unvaccinated compared to those vaccinated. In a time-varying Cox regression model with propensity score weight adjusted for, this translated to a VE of 22%.