Public Health and Communicable Diseases - SA Health - SA.Gov.au

Immunisation– a new era for vaccinesHelen MarshallHead, Paediatric Trials Unit,Women’s and Children’s HospitalClinical Lecturer, Dept of Paediatrics,University of AdelaideClinical Lecturer, Dept of Public Health,University of AdelaideVaccines prevent up to three million deaths eachyear and 750,000 children are saved from disabilityglobally. 1 Recent advances in immunisation include themanufacture of several new vaccines including vaccinesto prevent Rotavirus (RV), the commonest causeof gastroenteritis in children and a vaccine with thepotential to substantially reduce the incidence of cervicalcancer in women.Rotavirus VaccinesRotavirus InfectionRotavirus infection causes approximately 440,000deaths worldwide every year in children under 5 yearsof age. 2 Most deaths from gastroenteritis occur indeveloping countries where children can experiencegreater than 12 episodes of diarrhea per year. Almost allchildren have been infected with RV by 2-3 years of age. 3There are an estimated 10,000 hospital admissionsand 115,000 GP visits annually attributable to RVinfection in children < 5 years in Australia. 4 Importantlygastroenteritis is a leading cause of morbidity andmortality in aboriginal children in Australia. Five outof 14 major serotypes are associated with almost allhuman rotavirus infections: G1, G2, G3, G4 and G9. 5Rotavirus VaccineThe first live oral RV reassortment vaccine, RotaShieldwas shown to provide 48% - 68% protection againstany RV disease when administered at 2, 4 and 6months of age. Following licensing in the USA in 1998and introduction into the routine schedule, the vaccinewas withdrawn form the market in 1999 followingseveral cases of intussusception after immunisation.The decision to remove RotaShield from the childhoodschedule in the USA remains controversial. 6 The riskof intussusception following administration of thisvaccine has recently been reassessed and estimatedto be as low as 1:32,000 (background risk of 18 to 56cases per 100,000 infant years). 6 More recently twonew RV vaccines have been manufactured, which arelikely to be available for use in Australia in the next12 months. A pentavalent human-bovine reassortant(G1, G2, G3, G4 and P[8]), 3 dose oral vaccine hasbeen developed by Merck Research Co (Rotateq) and amonovalent (P[8] G1), live attenuated 2 dose oral vaccinehas been developed by Avant Immunotherapeuticsfrom a live human RV strain and licensed to GSK23Biologicals (Rotarix). Pre-licensure studies with samplesizes including >60,000 infants have shown bothvaccines to be safe and efficacious against RV infectionwith no increased risk of intussusception followingadministration of these vaccines (Rotateq: RR 1.6; (95%CI 0.4, 6.4), Rotarix: RR 0.85 (95% CI 0.30, 2.42). 7,8Use of the vaccines is likely to lead to a reduction inthe burden of disease and health care costs associatedwith RV infection in Australian communities, howeverthe most significant potential benefits are reduction ofmorbidity and mortality in the developing world. TheWorld Health Organization has prioritised RV vaccineresearch and the RV Vaccine Programme based at PATHin Seattle, USA, aided by the Global Alliance for Vaccinesand Immunisation (GAVI) is assessing the informationrequired for early rotavirus introduction and accelerateduse in the global community. In addition to establishingRotavirus Vaccine Programs, surveillance for adverseevents associated with use of the new vaccines isimperative.Human Papilloma Virus VaccinesCervical cancer is preceded only by breast cancer as themost common cause of death from cancer in womenworldwide. In developing countries, where mass cancerscreening is not well established, cervical cancer isthe leading cause of death from cancer in womenparticularly affecting the 35-55 year age group. Mostdeveloping countries either have ineffective Pap smearscreening programs or have no such programs at all. 9In developed countries there has been a significantreduction in morbidity and mortality from cervicalcarcinoma due to the success of routine screeningusing the Pap smear. 10 However, despite the successof screening programs there is still significant morbidityand mortality from this disease in our community.Unfortunately not all women present for regularscreening and histologic and cytologic assessmentsof pap smears are subjective and may be prone tooperator error. 10 Pap smear screening alone is thereforenot entirely satisfactory as a preventative method forcervical cancer, even in the developed world and indeveloping countries is not practical.Cervical Carcinoma in Australian WomenThere are approximately 800-1000 new cases of cervicalcarcinoma diagnosed in Australian women each year. 11It is the 14th most common cause of cancer deathin Australian women. The lifetime risk of a womandeveloping cervical cancer is one in 130. In the 4 yearperiod from 2000 to 2003 there were 994 deaths fromcervical cancer in all states and territories comparedwith 1,081 from 1996 to 1999. 12Among aboriginal women there is evidence of a higherrate of cervical cancer compared with non-aboriginalwomen. In the period between 1995 and 1997 therewere 19 deaths (27.6 per 100 000 women) from cervical