Immunity to hepatitis B, poliomyelitis and measles in fully vaccinated Aboriginal and Torres Strait Island children

Abstract

Although a relatively low proportion of the children had adequate antibody levels against hepatitis B the clinical significance of this observation is uncertain. Further studies are needed to determine whether fully vaccinated Torres Strait Island children have been adequately protected and whether they require a booster dose of hepatitis B vaccine. A substantial proportion of fully vaccinated Aboriginal and Torres Strait Island children are inadequately protected against poliomyelitis, and therefore any such child with acute flaccid paralysis should be investigated fully for poliomyelitis. Vaccinated Aboriginal and Torres Strait Island children are well protected against measles, as are other Australian children.

Screening for hepatitis B in East Arnhem Land: a high prevalence of chronic infection despite incomplete screening

“…This fact is often used to argue that HBV infection is no longer a public health problem; however, this audit demonstrates that this is not the case. Not only is there a large cohort of susceptible people born before 1990, but incomplete immunization, ongoing vertical transmission despite the use of hepatitis B immunoglobulin and a poor immune response to vaccination among Aboriginal children, means that HBV remains an ongoing public health problem in Aboriginal communities for all age groups 11,18 …”

“…Not only is there a large cohort of susceptible people born before 1990, but incomplete immunization, ongoing vertical transmission despite the use of hepatitis B immunoglobulin and a poor immune response to vaccination among Aboriginal children, means that HBV remains an ongoing public health problem in Aboriginal communities for all age groups. 11,18 We have assumed that patients with positive HBcAb, negative HBsAg and negative HBsAb (a pattern sometimes called 'indeterminate serology') have past infection. A small proportion of these patients may have detectable HBV DNA in plasma, and thus 'occult HBV infection'.…”

Measles immunity and immunisation status in Australian children 1 to 4 years of age

“…Our finding that 90% of reportedly immunised children were seropositive is lower than the 95% of children reported to seroconvert in clinical trials 10,11 . This may reflect lower frequency of seroconversion due to difficulties in vaccine delivery in practice, such as suboptimal vaccine storage, or may reflect over‐reporting of immunisation by parents, as suggested by Hawe et al 12 .…”

“…Our finding that 90% of reportedly immunised children were seropositive is lower than the 95% of children reported to seroconvert in clinical trials. 10,11 This may reflect lower frequency of seroconversion due to difficulties in vaccine delivery in practice, such as suboptimal vaccine storage, or may reflect over-reporting of immunisation by parents, as suggested by Hawe et al 12 If the latter, this would suggest that not only do parents erroneously recall vaccines that were not actually given but the unlikely possibility that immunisation records erroneously document such immunisations, given the proportion of children who were seropositive was the same regardless Immunised of source of immunisation history. Studies which cross-reference parental recall and immunisation records with the Australian Childhood Immunisation Register may clarify this.…”

Imported Case of Poliomyelitis, Melbourne, Australia, 2007

“…The high level of vaccination in Australia reduces the risk for local transmission after poliovirus importation. However, Australia has a large migrant population who might not be immune, and Aboriginal and Torres Strait Islanders exhibit reduced seroconversion rates after polio vaccination (10). Risk for local outbreaks can be minimized by widespread vaccination, early recognition of an index case, and prompt and appropriate public health measures.…”