RESUMO
Background: Few studies have examined effectiveness of COVID-19 vaccines against COVID-19 and all-cause mortality across different pandemic periods in 2022. Methods: We used linked whole-of-population data from the 2021 Australian Census, Australian Immunisation Register, death registrations and other national datasets including migration data. Among 3.8 million adults aged 65+ years and >170,000 aged care residents, we used survival analysis to estimate vaccine effectiveness (VE) against COVID-19 specific mortality and all-cause mortality, by vaccine dose and time since receipt, adjusted for age, sex and other factors. We also estimated absolute COVID-19 mortality rates. Findings: From January-May 2022 (Omicron BA.1/2), 3250 COVID-19 deaths occurred; from June-November (Omicron BA.4/5) 3185 COVID-19 deaths occurred. During January-May, VE of a 3rd COVID-19 vaccine dose within 3 months was 93% (95% CI 93-94%) whilst VE of a 2nd dose >6 months since receipt was 34% (26-42%). During June-November, VE of a 4th COVID-19 vaccine dose within 3 months was 84% (82-86%) whilst VE of a 3rd dose >6 months since receipt was 56% (50-62%). VE estimates for aged care residents were similar, but absolute risk reductions were substantially greater. During June-November 2022, for all-cause mortality, VE of a 4th dose within 3 months was 58% (56-59%) whilst VE of a 3rd dose >6 months since receipt was 19% (16-22%). Interpretations: COVID-19 vaccination is highly effective against COVID-19 mortality among older adults although effectiveness wanes with time since the last dose. Our findings emphasise the importance of continuing to administer booster doses, particularly to those at highest risk. Funding: This study was funded by the Health Economics Research Division in the Australian Government Department of Health and Aged Care.
RESUMO
In 2010, 65 diseases and conditions were nationally notifiable in Australia. States and territories reported a total of 209,079 notifications of communicable diseases to the National Notifiable Diseases Surveillance System, a decrease of 12% on the number of notifications in 2009. This decrease was largely due to a reduction of influenza compared with the influenza A(H1N1) pandemic 2009. In 2010, the most frequently notified diseases were sexually transmissible infections (86,620 notifications, 41.4% of total notifications), vaccine preventable diseases (61,964 notifications, 29.6% of total notifications), and gastrointestinal diseases (31,548 notifications, 15.1% of total notifications). There were 18,302 notifications of bloodborne diseases; 8,244 notifications of vectorborne diseases; 1,866 notifications of other bacterial infections; 532 notifications of zoonoses and 3 notifications of quarantinable diseases.
