Send to Vaccine. 2018 May 11;36(20):2794-2798. doi: 10.1016/j.vaccine.2018.03.086. Epub 2018 Apr 13. Australian rubella serosurvey 2012-2013: On track for elimination? Edirisuriya C1, Beard FH2, Hendry AJ3, Dey A4, Gidding HF5, Hueston L6, Dwyer DE6, Wood JG7, Macartney KK4, McIntyre PB4. Author information Abstract BACKGROUND: The World Health Organization has targeted rubella virus for elimination regionally. Australia was one of the first countries to implement a nationally funded rubella immunisation program, in 1971, and conducts regular national rubella serosurveillance studies. We aimed to estimate the seroprevalence of rubella-specific IgG antibody in the Australian population by age and sex in 2012-2013, to compare the results with three previous serosurveys conducted in 1996-1999, 2002 and 2007 and to estimate the effective reproduction numbers (Rn). METHODS: This study used 2729 serum and plasma specimens, randomly selected from a specimen bank collected in 2012-2013 across Australia. Age groups included in the sample ranged from 1 to 49 years. Sera were tested for rubella-specific IgG-antibody using the Enzygnost anti-rubella IgG enzyme immunoassay and classified as positive, negative or equivocal according to rubella-specific IgG concentrations of >7 IU/ml, <3 IU/ml and 3-7 IU/ml, respectively. RESULTS: The overall proportions seropositive, seronegative and equivocal for rubella-specific IgG were 92.1% (95% CI, 91.0-93.2), 6.7% (95% CI, 5.7-7.7) and 1.2% (95% CI, 0.8-1.6), respectively. The proportion of males seropositive was significantly lower than females in the 30-34 (83.1% vs. 96.8%, p = 0.003), 35-39 (86.1% vs. 96.3%, p = 0.02) and 40-44 (86.1% vs. 95.7%, p = 0.03) year age groups. Rn for rubella in 2012-2013 was estimated to be 0.33 (95% CI 0.28-0.39). DISCUSSION: The 2012-2013 national serosurvey showed levels of rubella-specific IgG seropositivity in the Australian population are relatively high with no evidence of decrease compared to previous serosurveys conducted in 1996-1999, 2002 and 2007. The lower proportion of seropositive males aged 30-44 years likely reflects the initial immunisation program targeting females only. To our knowledge this study represents the longest period of serosurveillance following introduction of a nationally funded rubella immunisation program. The lack of evidence of decreasing rubella-specific IgG seropositivity is therefore reassuring for Australia and other countries with longstanding high vaccine coverage. Copyright © 2018 The Author(s). Published by Elsevier Ltd.. All rights reserved.

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Vaccine. 2018 May 11;36(20):2794-2798. doi: 10.1016/j.vaccine.2018.03.086. Epub 2018 Apr 13.

Australian rubella serosurvey 2012-2013: On track for elimination?

Edirisuriya C1 Beard FH2 Hendry AJ3 Dey A4 Gidding HF5 Hueston L6 Dwyer DE6 Wood JG7 Macartney KK4 McIntyre PB4.

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Abstract

BACKGROUND:

The World Health Organization has targeted rubella virus for elimination regionally. Australia was one of the first countries to implement a nationally funded rubella immunisation program in 1971 and conducts regular national rubella serosurveillance studies. We aimed to estimate the seroprevalence of rubella-specific IgG antibody in the Australian population by age and sex in 2012-2013 to compare the results with three previous serosurveys conducted in 1996-1999 2002 and 2007 and to estimate the effective reproduction numbers (Rn).

METHODS:

This study used 2729 serum and plasma specimens randomly selected from a specimen bank collected in 2012-2013 across Australia. Age groups included in the sample ranged from 1 to 49 years. Sera were tested for rubella-specific IgG-antibody using the Enzygnost anti-rubella IgG enzyme immunoassay and classified as positive negative or equivocal according to rubella-specific IgG concentrations of >7 IU/ml <3 IU/ml and 3-7 IU/ml respectively.

RESULTS:

The overall proportions seropositive seronegative and equivocal for rubella-specific IgG were 92.1% (95% CI 91.0-93.2) 6.7% (95% CI 5.7-7.7) and 1.2% (95% CI 0.8-1.6) respectively. The proportion of males seropositive was significantly lower than females in the 30-34 (83.1% vs. 96.8% p = 0.003) 35-39 (86.1% vs. 96.3% p = 0.02) and 40-44 (86.1% vs. 95.7% p = 0.03) year age groups. Rn for rubellain 2012-2013 was estimated to be 0.33 (95% CI 0.28-0.39).

DISCUSSION:

The 2012-2013 national serosurvey showed levels of rubella-specific IgG seropositivity in the Australian population are relatively high with no evidence of decrease compared to previous serosurveys conducted in 1996-1999 2002 and 2007. The lower proportion of seropositive males aged 30-44 years likely reflects the initial immunisation program targeting females only. To our knowledge this study represents the longest period of serosurveillance following introduction of a nationally funded rubella immunisation program. The lack of evidence of decreasing rubella-specific IgG seropositivity is therefore reassuring for Australia and other countries with longstanding high vaccine coverage.

Copyright © 2018 The Author(s). Published by Elsevier Ltd.. All rights reserved.

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