Effectiveness of cocoon strategy vaccination on prevention of influenza-like illness in young infants

ABSTRACT

During the initial half-year of their existence, infants cannot receive the influenza vaccine, yet they face the greatest susceptibility to severe influenza complications. In this study, we seek to determine whether influenza vaccination of maternal and household contacts is associated with a reduced risk of influenza-like illness (ILI) and severe acute respiratory infection (SARI) in infants. This work was prospectively conducted during the influenza season. A total of 206 infants were included in this study. The percentage of infants with only the mother vaccinated is 12.6% (n:26), and the percent of infants with all household contacts vaccinated is 16% (n:33). Among the infants with only the mother vaccinated, the effectiveness of influenza vaccine is estimated as 35.3% for ILI and 41.3% for SARI. Among infants with all household contacts vaccinated, the effectiveness is estimated as 48.9% for ILI and 76.9% for SARI. Based on the results of multivariate logistic regression analysis, all-household vaccination is a protective factor against SARI (OR: 0.07 95% CI [0.01–0.56]), household size (OR: 1.75, 95% CI [1.24–2.48]) and presence of secondhand smoke (OR: 2.2, 95% CI [1.12–4.45]) significant risk factors for SARI in infants. The mother alone being vaccinated is not a statistically significant protective factor against ILI (OR: 0.46, 95% CI [0.19–1.18]) or SARI (OR: 0.3, 95% CI [0.11–1.21]). Along with the obtained results and analysis, this study provides clear evidence that influenza vaccination of all household contacts of infants aged 0–6 months is significantly associated with protecting infants from both ILI and SARI.

KEYWORDS:

• Cocooning
• influenza
• influenza-like illness
• severe acute respiratory infection

Disclosure statement

No potential conflict of interest was reported by the author(s).

Author contribution

Oguz MM and Senel S and designed the study; Oguz MM collected and analyzed data; Oguz MM wrote the manuscript. Senel S and Oguz MM made important intellectual/conceptual critical corrections for preparation of study design and for the content. All authors read and approved the final manuscript. The authors report there are no competing interests to declare.

Additional information

Funding

The author(s) reported there is no funding associated with the work featured in this article.