Infant contact in day-care centres in Vietnam: A cross-sectional study to understand infant infection risk.

Background : Infant contact information (skin-to-skin contact between infants and others) is important to understand Streptococcus pneumoniae transmission patterns. A few studies have investigated infant contact patterns by asking the mother/guardian to record all contacts a child makes in one day. However, this approach does not capture contact behaviour in day-care. Our study describes the frequency and nature of physical contacts of infants in day-care to understand infant infection risk in day-care in Nha Trang, central Vietnam. Methods : This cross-sectional study enrolled infants aged less than 12 months, attending 10 randomly selected day-care centres in Nha Trang. Physical contacts of each infant for one day at the day-care centre were observed and recorded. The mean number of contacts of infants and its factors were assessed using negative binomial regression. Results : In total 14 infants, aged 6 to 11 months, were enrolled, and a total of 96 contacts were observed. The mean number of contacts an infant made in one day was 6.9. Infants who walked independently (age-adjusted rate ratio 1.68, 95% confidence interval 1.06-2.68) and those cared for in a larger group (1.99, 1.42-2.79) had more contacts at day-care. About 50% of infants made contact with at least one person from a commune different from the infant's, and 50% made contact with at least one other infant at day-care. Conclusion : This study found that day-care attendance may be one factor that increases contact rates of infants in Nha Trang and diversifies them in terms of age and geographical spread. In this study, day-care attendance not only increased contact rates beyond those usually experienced by young children cared at home but specifically increased the contact rates with other children and adults from other communes. Day-care may play a key role in the transmission of respiratory pathogens like Streptococcus pneumoniae to infants.