To determine the effect of moderate altitude on arterial oxygen saturation (SaO2), pulse oximetry was performed on 302 children aged <3 months attending a clinic in Goroka, Eastern Highlands Province (1584 metres above sea level) for minor ailments or immunization. Respiratory and heart rates were also measured. The overall mean SaO2 was 96%. Comparison between log-transformed means showed that SaO2 was significantly lower in the first month of life than later (p=0.04). 6% of SaO2 values were <92%, which is a practical cut-off for normal SaO2 in this population of highland children aged <3 months. Mean respiratory and heart rates were 50/minute and 145/minute, respectively. After adjusting for age, respiratory rate increased significantly as SaO2 declined (p=0.002). We have thus defined reference values for SaO2, respiratory rate and heart rate in healthy young infants residing in the highlands of Papua New Guinea. Further investigation is needed to determine whether SaO2 is lower in babies when they are asleep and to define reference values for older children in the highlands.
Heart Rate - physiology ; Infant, Newborn ; Linear Models ; Oximetry ; Oxygen - blood ; Papua New Guinea - epidemiology ; Respiration

Infants in Papua New Guinea (PNG) are at a high risk of invasive pneumococcal disease, and a substantial burden of this falls on children less than six months old. PNG is planning to introduce a pneumococcal conjugate vaccine for infants in the near future, but to make the maximum impact neonatal immunization will have to be considered. To provide evidence on safety and immunogenicity for neonatal and early infant immunization, we undertook an open randomized controlled trial of 7-valent pneumococcal conjugate vaccine (7vPCV). 318 children received 7vPCV at ages 0, 1 and 2 months or at 1, 2 and 3 months or not at all. All children received 23-valent pneumococcal polysaccharide vaccine at age 9 months. This was a large and complex trial: village reporters visited participants weekly during the first year and fortnightly for a further 6 months and nurses monitored self-reported morbidity and collected many thousands of biological samples. The study team was remarkably successful in achieving the study aims, with 18-month follow-up completed on 77% of enrolled children and over 80% of scheduled samples collected. While the results of the trial will be reported elsewhere, this paper discusses the design of the study and dissects out some of the main reasons for its successful completion. Strong community engagement was an essential factor in success and the principles of equitable partnership and service provision led to a strong research partnership. A two-stage consent process, comprising primary assent followed by later informed consent, led to a high drop-out before initial enrolment, but an outstanding retention of those enrolled in the study. We conclude that factors such as strong community participation, reciprocity and a good relationship between the study team and participants are just as important as the technical elements of laboratory testing and data handling in ensuring the success of a vaccine trial in PNG.