Limited impact of neonatal or early infant schedules of 7-valent pneumococcal conjugate vaccination on nasopharyngeal carriage of Streptococcus pneumoniae in Papua New Guinean children: A randomized controlled trial.

Streptococcus pneumoniae is a leading cause of pneumonia, the most common cause of childhood death. Papua New Guinean children experience high rates of nasopharyngeal pneumococcal colonization within weeks of birth, predisposing them to pneumococcal disease. In a trial to determine the safety and immunogenicity of early infant vaccination with 7-valent pneumococcal conjugate vaccine (7vPCV), we investigated the impact of early schedules on pneumococcal carriage. Infants were randomized at birth to receive 7vPCV in a 0-1-2-month (n = 101) or a 1-2-3-month (n = 105) schedule or no 7vPCV (n = 106). All children received 23-valent pneumococcal polysaccharide vaccine at age 9 months. We cultured nasopharyngeal swabs (NPS) collected at ages 1, 2, 3, 4 weeks and 3, 9, 18 months, and middle ear discharge if present. Pneumococcal serotypes were identified by the Quellung reaction. A total of 1761 NPS were cultured. The prevalence of pneumococcal carriage was 22% at 1 week of age, rising to 80% by age 3 months and remained >70% thereafter, with high-density carriage in 42% of pneumococcus-positive samples. We identified 63 different serotypes; 43% of isolates from controls were 13vPCV serotypes. There were no significant differences in 7vPCV serotype carriage between 7vPCV recipients and controls at any age (22% vs. 31% at 9 months, p = 0.2). At age 9 months the prevalence of non-7vPCV carriage was 17% higher in 7vPCV recipients (48%) than in controls (25%, p = 0.02). More non-7vPCV serotypes were isolated from ear discharge in 16 7vPCV recipients than from 4 controls (48% vs. 25%, p = 0.13). The limited impact of neonatal or accelerated infant 7vPCV schedules on vaccine serotype carriage is probably due to the early onset of dense carriage of a broad range of pneumococcal serotypes. While serotype-independent pneumococcal vaccines are needed in high-risk populations, the underlying environmental factors and sources of infection must be investigated. http://clinicaltrials.gov/ct2/show/NCT00219401.

Epidemic malaria in the highlands of Papua New Guinea.

As part of a larger study into the epidemiology of malaria in the highlands of Papua New Guinea, outbreak investigations were carried out at the end of the 2002 rainy season in 11 villages situated between 1,400 and 1,700 meters above sea level that had reported epidemics. Locations and timing of these epidemics corresponded largely to those reported in the pre-control era of the 1960s and 1970s. On average, 28.8% (range = 10.3-63.2%) of people in each of the 11 villages were found to be infected with malaria. Plasmodium falciparum accounted for 59% of all identified infections and P. vivax for 34%. The majority (53%) of infections were symptomatic. Although symptomatic infections were most common in children 2-9 years of age (36%), even in adults a prevalence of 20% was observed. A comparison with earlier non-epidemic data in three of the villages without easy access to health care showed markedly increased levels of morbidity, with 6-10-fold increases in parasite prevalence, a 3-fold increase in both measured and reported fevers, and a 12-fold increase in enlarged spleens. The average hemoglobin levels were reduced by 2.3-3.5 g/dL, with a concurrent increase in moderate to severe anemia (hemoglobin level < 7.5 g/dL) from 0.0-3.3% to 3.8-18.4%. These massive increases in morbidity have devastating impact on the affected communities and highlight that malaria epidemics are a serious and increasing public health problem in the highlands of Papua New Guinea.

Barriers to measles immunization: the beliefs and attitudes of caregivers in Goroka, Eastern Highlands Province, Papua New Guinea.

In Papua New Guinea, measles remains a public health problem and the majority of measles cases occur in non-immunized children. In Goroka, measles vaccine coverage for the 9-month-old group was 44%. The parents or caregivers are important in measles prevention as children's immunization depends on their compliance. This study aimed to determine the factors that hinder caregivers from having their children vaccinated for measles prevention in the Goroka District, Eastern Highlands Province. A cross-sectional study was conducted in July-August 2003, using pre-constructed questionnaires and interviews. There was a total of 120 respondents who were caregivers or parents of children whose ages ranged from 6 to 12 months and who attended health care centres where immunization services were provided. The main reasons for not bringing their children to clinic for immunization were: limited access to health centres, especially to maternal and child health (MCH) clinics; too long a waiting time at the clinic; concern that too many injections were being given to their children; the side-effects of the vaccine; being sent away and asked to come back the next day for immunization; and a bad reception from health workers. Funerals or election-related events in the area also affected the attendance at the clinic. In order to improve the vaccine coverage, the use of a mobile MCH clinic should be re-established. Health workers should utilize the opportunities to pass on necessary information on immunization to caregivers, as well as being mindful to use communication that will prevent misunderstanding by the mothers. It is important for all health workers to recognize that their performance and attitude can greatly improve the overall vaccine coverage in Papua New Guinea.

The epidemiology of malaria in the Papua New Guinea highlands: 3. Simbu Province.

Two very distinct malaria zones can be found within Simbu Province. The north of the province is characterized by the absence or very low level of local malaria transmission, but there is a considerable risk of epidemics prevalent in the lower-lying parts. During non-epidemic periods, parasite prevalence was usually under 5%, with similar frequencies for Plasmodium falciparum and P. vivax (47% each), and malaria was an only minor source of febrile illness. During epidemics, however, 13-36% of people were infected, predominantly with P. falciparum (64%), and high levels of severe morbidity were present. In south Simbu malaria is clearly endemic with an overall prevalence of 35%, combined with a strong age-dependence of infections, low haemoglobin levels, high rates of enlarged spleen and moderate to severe anaemia (haemoglobin level < 7.5 g/dl) in children. The malaria epidemiology in south Simbu is thus more similar to the lowlands than to other highlands areas. Epidemic prevention, surveillance and response in the north, and bednet distribution and strengthening of curative services in the south, are therefore the priorities for malaria control in Simbu Province.