Michelle Clarke

Direct and indirect impact on rotavirus positive and all-cause gastroenteritis hospitalisations in South Australian children following the introduction of rotavirus vaccination.

Rotavirus vaccine for infants was introduced into the National Immunisation Program in Australia in July 2007. To determine the impact of rotavirus vaccination on gastroenteritis hospitalisations amongst children less than six years of age in South Australia, we conducted a retrospective analysis of hospital admissions over two time periods: 1 May 2005-30 April 2007 (prior to rotavirus vaccination introduction) and 1 May 2008-30 April 2010 (post rotavirus vaccination introduction). The introduction of rotavirus vaccination has been associated with a marked reduction in hospital admissions for serious rotavirus gastroenteritis (RVGE) and all-cause gastroenteritis (ACGE). Following the introduction of rotavirus vaccination in South Australia, there was an 83% reduction in RVGE coded admissions (955 vs 165) and a 48% reduction in ACGE coded admissions (4153 vs 2142) for children aged less than six years. Children less than two years demonstrated the greatest reduction (90%) in RVGE admissions and ACGE admissions (57%). Age-specific RVGE hospitalisation rates decreased from 933/100,000 prior to rotavirus vaccine introduction to 88/100,000 for children less than two years of age. In addition, for gastroenteritis hospitalisations for children aged five years at time of admission (unvaccinated cohort) there was a reduction in the number of RVGE cases (24 vs 4), a reduction in age-specific RVGE hospitalisation rates (65/100,000 vs 11/100,000) and a significant reduction in the proportion of overall gastroenteritis cases which were rotavirus positive (11.5% vs 3.5%), suggesting a positive impact on both unvaccinated and vaccinated children less than six years of age in South Australia.

Ultrasound examination of extensive limb swelling reactions after diphtheria-tetanus-acellular pertussis or reduced-antigen content diphtheria-tetanus-acellular pertussis immunization in preschool-aged children.

OBJECTIVE. The aim of this study was to determine the site, extent, and resolution of tissue involvement when extensive limb swelling occurred in the injected limb for children who received diphtheria-tetanus-acellular pertussis or reduced-antigen content diphtheria-tetanus-acellular pertussis vaccine at 4 to 6 years of age. METHODS. Children who had experienced an injection site reaction at 18 months of age were assigned randomly to receive an intramuscular injection of either reduced-antigen content diphtheria-tetanus-acellular pertussis vaccine or diphtheria-tetanus-acellular pertussis vaccine between 4 and 6 years of age. Children who developed extensive limb swelling were recruited for assessment by clinical examination; ultrasound studies of the affected and opposite (control) arms were performed 24 to 48 hours after immunization and 48 to 96 hours later. RESULTS. Twelve children with extensive limb swelling were enrolled in the study. Ultrasound examinations demonstrated swelling of both the subcutaneous and muscle layers of the vaccinated arm. Ultrasound assessment showed that the swelling exceeded the clinical measurements of skin redness and swelling. Subcutaneous and muscle tissues expanded to 281% and 111% of the tissue thicknesses of the control arm, respectively. Repeat ultrasound examinations after 48 to 96 hours showed considerable resolution of muscle swelling, compared with subcutaneous tissue swelling. There was no significant difference in the extent of swelling detected between children who received diphtheria-tetanus-acellular pertussis vaccine and those who received reduced-antigen content diphtheria-tetanus-acellular pertussis vaccine. CONCLUSION. Extensive limb swelling reactions after diphtheria-tetanus-acellular pertussis or reduced-antigen content booster immunizations involved swelling of subcutaneous and muscle tissues with swelling and duration more marked in subcutaneous tissue.

Predictors of Disease Severity in Children Hospitalized for Pertussis during an Epidemic

Background: Australia recently experienced its worst pertussis epidemic since introduction of pertussis vaccine into the National Immunisation Program. This study aimed to determine factors associated with severe pertussis in hospitalized children during an epidemic using a novel pertussis severity scoring (PSS) system. Methods: This prospective, observational, multicenter study enrolled children hospitalized with laboratory confirmed pertussis from 8 tertiary pediatric hospitals during a 12 month period (May 2009–April 2010). Variables assessed included demographics, clinical symptoms and relevant medical and immunization history. Cases were scored using objective clinical findings with cases classified as either severe (PSS > 5) or not severe (PSS ⩽ 5). Logistic regression models were used to predict variables associated with severe disease. Results: One hundred twenty hospitalized children 0–17 years of age were enrolled with a median PSS of 5 (interquartile range 3–7). Most (61.7%) were classified as not severe with 38.3% (46/120) severe. Most severe cases (54.3%) were <2 months of age. Presence of coinfection [odds ratio (OR): 4.82, CI: 1.66–14.00], <2 months old (OR: 4.76, CI: 1.48–15.32), fever >37.5°C (OR: 5.97, CI: 1.19–29.96) and history of prematurity (OR: 5.00, CI: 1.27–19.71) were independently associated with severe disease. A total of 70 cases in children ≥2 months of age, almost a third (n = 23) had not received pertussis vaccine. Conclusions: Most severe pertussis occurred in young, unimmunized infants, although severe disease was also observed in children >12 months of age and previously vaccinated children. Children admitted with pertussis with evidence of coinfection, history of prematurity or fever on presentation need close monitoring.

Parental and community acceptance of the benefits and risks associated with meningococcal B vaccines

OBJECTIVE A new meningococcal serogroup B (Men B) vaccine has been licensed in the European Union (EU) and Australia. This study aimed to assess community and parental attitudes to introduction of new Men B vaccines and identify facilitators and barriers to vaccine implementation. METHODS Cross-sectional survey including face-to-face interviews with adolescents, parents and adults from randomly selected households in South Australia in 2012. Survey data were weighted to the age, gender and geographical area profile of the population. RESULTS 3055 interviews were conducted with individuals aged 15-97 years, including 966 parents. Participation rate was 66.4%. 82.5% (95% CI 79.7-85.4) of parents (797/966) wanted their child to receive the Men B vaccine, with 12.2% (9.7-14.7) (118/966) unsure. Main parental concerns included potential side effects (41.3% (26.7-46.0)) and adequate vaccine testing (11.7% (9.4-14.1)). Potential for an extra injection at an immunisation visit resulted in 15.7% (12.8-18.5) of parents (n=152/966) less likely to have their child immunised. Potential redness/swelling at the injection site or mild/moderate fever resulted in only 8.5% (6.3-10.7) and 10.8% (8.5-13.2) of parents, respectively, less likely to have their child immunised. Children being up to date with vaccinations and recommendation from family physician were the strongest independent predictors of parents agreeing their children should be immunised with Men B vaccine (OR=6.58; p=0.006 and OR=4.15; p<0.001, respectively). Only 16.4% (14.9-17.9) of adults (501/3055) stated that they would not want to receive a Men B vaccine, with family physician recommendation the strongest independent predictor of acceptance (OR=3.81; p<0.001). CONCLUSIONS There is strong community support for introduction of Men B vaccines, with parental willingness to have children immunised, impacted more by number of injections than potential for adverse events such as local reactions or fever.

Maternal uptake of pertussis cocooning strategy and other pregnancy related recommended immunizations

Maternal immunization is an important strategy to prevent severe morbidity and mortality in mothers and their offspring. This study aimed to identify whether new parents were following immunization recommendations prior to pregnancy, during pregnancy, and postnatally. A cross-sectional survey was conducted by a questionnaire administered antenatally to pregnant women attending a maternity hospital with a follow-up telephone interview at 8–10 weeks post-delivery. Factors associated with uptake of pertussis vaccination within the previous 5 y or postnatally and influenza vaccination during pregnancy were explored using log binomial regression models. A total of 297 pregnant women completed the questionnaire. For influenza vaccine, 20.3% were immunized during pregnancy and 3.0% postnatally. For pertussis vaccine, 13.1% were vaccinated within 5 y prior to pregnancy and 31 women received the vaccine postnatally, 16 (51.6%) received the vaccine >4 weeks after delivery. Receiving a recommendation from a healthcare provider (HCP) was an independent predictor for receipt of both pertussis (RR 2.07, p < 0.001) and influenza vaccine (RR 2.26, p = 0.001). Non-English speaking mothers were significantly less likely to have received pertussis vaccination prior to pregnancy or postnatally (RR 0.24, p = 0.011). Multiparous pregnant women were less likely to have received an influenza vaccine during their current pregnancy (p = 0.015). Uptake of pregnancy related immunization is low and likely due to poor knowledge of availability, language barriers and lack of recommendations from HCPs. Strategies to improve maternal vaccine uptake should include education about recommended vaccines for both HCPs and parents and written information in a variety of languages.

Adolescent, parent and societal preferences and willingness to pay for meningococcal B vaccine: a Discrete Choice Experiment

OBJECTIVE Meningococcal B (MenB) vaccines have been licensed in many countries with private purchase the only option until recently, when a funded programme was introduced in the UK. The aim of this study was to explore adolescent/parental values for a variety of salient vaccine attributes (cost, effectiveness, side effect profile) to assess preferences and willingness-to-pay (WTP) for a MenB vaccine. METHODOLOGY A national cross-sectional population study was conducted in Australia using Discrete Choice Experiment methodology to assess adolescent/parent/adult preferences for attributes related to MenB vaccine. RESULTS 2003 adults and 502 adolescents completed the survey in 2013. The majority of participants were willing to be vaccinated with MenB vaccine with vaccination opt-out chosen by 11.9% of adolescents and parents, and 18.2% of non-parent adults. A mixed logit regression model examining adolescent/adult preferences indicated consistent findings; the higher the effectiveness, the longer the duration of protection, the less chance of adverse events and the lower the cost, the more likely respondents were to agree to vaccination. For an ideal MenB vaccine, including the most favoured level of each attribute summed together (90% effectiveness, 10 year duration, 1 injection, no adverse events) adolescents would pay AU

Safety of Tetanus, Diphtheria, and Pertussis Vaccination During Pregnancy: A Systematic Review.

251.60 and parents AU

Community, parental and adolescent awareness and knowledge of meningococcal disease.

295.10. Adolescents and parents would pay AU

The pertussis epidemic: informing strategies for prevention of severe disease

90.70 or AU

The clinical burden and predictors of sequelae following invasive meningococcal disease in Australian children.

127.20 for 90% vaccine effectiveness vs AU