Pertussis Morbidity in Children 12-59 Months of Age: A NSW Public Health Network Study.

BACKGROUND: Pertussis continues to be a significant public health problem despite high levels of vaccination. Although hospitalizations and deaths among children greater than 12 months of age are much less frequent than among infants less than 6 months of age, only limited information is available for this age group on other measures of morbidity. METHODS: A cross-sectional study with a 6-week follow-up component was conducted in New South Wales, Australia in 2017 to measure morbidity among children 12-59 months of age notified to health authorities. Measures used included cough duration, cough severity, constitutional symptoms and impacts on the family. Associations between these outcomes and age group, vaccination status, asthma, treatment and family structure were explored. RESULTS: Three hundred and five of 472 (65%) notified cases were interviewed at baseline with approximately 20% having a severe cough with no trend in prevalence across age groups. Forty-eight percent of cases had experienced 3 or more constitutional symptoms with rates significantly higher among younger children. Children who had received an 18-month booster vaccination were significantly less likely to experience 3 or more constitutional symptoms (odds ratio: 0.46, 95% confidence interval: 0.22-0.97). Fifty-one percent of cases were still coughing at 6 weeks. One-third of carers initially reported having disrupted sleep 4 or more nights per week with substantial disruption to carers' sleep still recorded at 6 weeks. CONCLUSIONS: Substantial morbidity was observed in this age group with some evidence that the reintroduction of an 18-month acellular pertussis booster lessened disease severity.

The changing and dynamic epidemiology of meningococcal disease.

The epidemiology of invasive meningococcal disease continues to change rapidly, even in the three years since the first Meningococcal Exchange Meeting in 2008. Control of disease caused by serogroup C has been achieved in countries that have implemented meningococcal C or quadrivalent meningococcal ACWY conjugate vaccines. Initiation of mass immunization programs with meningococcal A conjugate vaccines across the meningitis belt of Africa may lead to the interruption of cyclical meningococcal epidemics. A meningococcal B vaccination program in New Zealand has led to a decreased incidence of high rates of endemic serogroup B disease. Increases in serogroup Y disease have been observed in certain Nordic countries which, if they persist, may require consideration of use of a multiple serogroup vaccine. The imminent availability of recombinant broadly protective serogroup B vaccines may provide the tools for further control of invasive meningococcal disease in areas where serogroup B disease predominates. Continued surveillance of meningococcal disease is essential; ongoing global efforts to improve the completeness of reporting are required.

Modern trends in mortality from meningococcal disease in Australia.

Between 1979 and 2006, there were 610 deaths recorded as due to meningococcal disease in Australia. Mortality rates per capita consistently increased on average by 6% per annum between 1979 and 2002, but then fell significantly in 2003, coinciding with the introduction of the meningococcal C conjugate vaccine. In 2002, the mortality rate was 0.24 per 100,000. In the 4 years since, it fell progressively to 0.06 per 100,000. Since the introduction of conjugate Hib and pneumococcal vaccines, meningococcal disease has emerged as the number 1 infectious cause of death in children but conjugate meningococcal C vaccine appears to have greatly reduced total meningococcal disease deaths.