Background Developed countries have exhibited higher rates of PICU admission and case fatalities in male infants compared to females (Scott Watson et al, Am J Respir Crit Care Med, 2003). Contrastingly, in addition to the disease-specific protection vaccination offers, observational studies and randomised trials in developing countries have indicated there may also be non-specific effects to such vaccines, particularly in females (Aaby et al, PIDJ, 2007). Specifically, the diphtheria–tetanus–pertussis (DTP) vaccine has been associated with poor growth and increased morbidity in girls (Agergaard et al, Vaccine, 2011). Recent studies continue to highlight female infant mortality following early DTP vaccination within developing countries (Abay et al, Arch Dis Child, 2012).

Aims Expanding last years database to 5 years of PICU admissions, we hypothesise that non-specific vaccine effects would be demonstrated by differences in gender mortality and admission to PICU in infants with life-threatening infection.

Method Using the UK PICANET database from January 2006 to December 2010 we gathered a database of 38,157 infants <12 months of age. Stringent criteria excluded planned admissions, non-infectious aetiologies, and infants of unknown gender. Cohorts where then categorised into those >6 months and those <6 months, with the assumption that all those >6 months of age have received their primary course of DTP/IPV immunisation. From this, we established mortality percentages for females and males admitted due to infectious causes within their age-defined groups.

Results Total infant PICU admissions due to infectious causes were greater in both male cohorts compared to female cohorts (M < 6-months = 3,592, F < 6-months = 2,468; M > 6-months = 1,020, F > 6-months = 781). However, female mortality due to infectious causes for admission was greater than male mortality in both the under 6-month cohort (F = 4.94%, M = 3.54%) and the over 6-month cohort (F = 6.27%, M = 5.10%).

Conclusion Further analysis persistently displays increased female mortality percentages within both cohorts of infants. This recurrence is greater due to a greater population thereby; the expansion of data has yielded stronger correlations. With the help of PICANET epidemiologist, we are increasing this population size further and focusing on admissions related to respiratory infections.