Effectiveness of 7-valent pneumococcal conjugate vaccine against radiologically diagnosed pneumonia in indigenous infants in Australia

O'Grady, K.F., Carlin, J.B., Chang, A.B., Torzillo, P.J., Nolan, T.M., Ruben, A., & Andrews, R.M. (2010) Effectiveness of 7-valent pneumococcal conjugate vaccine against radiologically diagnosed pneumonia in indigenous infants in Australia. Bulletin of the World Health Organization, 88(2), pp. 139-146.

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Abstract

Objective

To evaluate the effectiveness of the 7-valent pneumococcal conjugate vaccine (PCV7) in preventing pneumonia, diagnosed radiologically according to World Health Organization (WHO) criteria, among indigenous infants in the Northern Territory of Australia.

Methods

We conducted a historical cohort study of consecutive indigenous birth cohorts between 1 April 1998 and 28 February 2005. Children were followed up to 18 months of age. The PCV7 programme commenced on 1 June 2001. All chest X-rays taken within 3 days of any hospitalization were assessed. The primary endpoint was a first episode of WHO-defined pneumonia requiring hospitalization. Cox proportional hazards models were used to compare disease incidence.

Findings

There were 526 pneumonia events among 10 600 children - an incidence of 3.3 per 1000 child-months; 183 episodes (34.8%) occurred before 5 months of age and 247 (47.0%) by 7 months. Of the children studied, 27% had received 3 doses of vaccine by 7 months of age. Hazard ratios for endpoint pneumonia were 1.01 for 1 versus 0 doses; 1.03 for 2 versus 0 doses; and 0.84 for 3 versus 0 doses.

Conclusion

There was limited evidence that PCV7 reduced the incidence of radiologically confirmed pneumonia among Northern Territory indigenous infants, although there was a non-significant trend towards an effect after receipt of the third dose. These findings might be explained by lack of timely vaccination and/or occurrence of disease at an early age. Additionally, the relative contribution of vaccine-type pneumococcus to severe pneumonia in a setting where multiple other pathogens are prevalent may differ with respect to other settings where vaccine efficacy has been clearly established.

Impact and interest:

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ID Code: 64715
Item Type: Journal Article
Refereed: Yes
Additional Information: 561HH
Times Cited:3
Cited References Count:31
Additional URLs:
Keywords: c-reactive protein, community-acquired pneumonia, acute respiratory-infections, placebo-controlled-trial, aboriginal children, otitis-media, disease burden, double-blind, efficacy, procalcitonin
DOI: 10.2471/BLT.09.068239
ISSN: 0042-9686
Subjects: Australian and New Zealand Standard Research Classification > MEDICAL AND HEALTH SCIENCES (110000)
Divisions: Current > QUT Faculties and Divisions > Faculty of Health
Funding:
Deposited On: 25 Nov 2013 22:31
Last Modified: 29 Jan 2015 00:23

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