Limits...
Age-specific incidence of A/H1N1 2009 influenza infection in England from sequential antibody prevalence data using likelihood-based estimation.

Baguelin M, Hoschler K, Stanford E, Waight P, Hardelid P, Andrews N, Miller E - PLoS ONE (2011)

Bottom Line: This method is applied to derive the cumulative and weekly incidence of A/H1N1 pandemic influenza in England during the second wave using sera taken between September 2009 and February 2010 in four age groups (1-4, 5-14, 15-24, 25-44 years).The highest cumulative incidence was in 5-14 year olds (59%, 95% credible interval (CI): 52%, 68%) followed by 1-4 year olds (49%, 95% CI: 38%, 61%), rates 20 and 40 times higher respectively than estimated from clinical surveillance.The method provides a more accurate and continuous measure of incidence than achieved by comparing prevalence in samples grouped by time period.

View Article: PubMed Central - PubMed

Affiliation: Immunisation, Hepatitis and Blood Safety Department, Health Protection Agency, London, United Kingdom. marc.baguelin@hpa.org.uk

ABSTRACT
Estimating the age-specific incidence of an emerging pathogen is essential for understanding its severity and transmission dynamics. This paper describes a statistical method that uses likelihoods to estimate incidence from sequential serological data. The method requires information on seroconversion intervals and allows integration of information on the temporal distribution of cases from clinical surveillance. Among a family of candidate incidences, a likelihood function is derived by reconstructing the change in seroprevalence from seroconversion following infection and comparing it with the observed sequence of positivity among the samples. This method is applied to derive the cumulative and weekly incidence of A/H1N1 pandemic influenza in England during the second wave using sera taken between September 2009 and February 2010 in four age groups (1-4, 5-14, 15-24, 25-44 years). The highest cumulative incidence was in 5-14 year olds (59%, 95% credible interval (CI): 52%, 68%) followed by 1-4 year olds (49%, 95% CI: 38%, 61%), rates 20 and 40 times higher respectively than estimated from clinical surveillance. The method provides a more accurate and continuous measure of incidence than achieved by comparing prevalence in samples grouped by time period.

Show MeSH

Related in: MedlinePlus

Posterior distribution of the cumulated incidences.Estimated cumulated incidence distributions for age-groups 1–4, 5–14, 15–24, 25–44 years during the second wave.
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC3044152&req=5

pone-0017074-g003: Posterior distribution of the cumulated incidences.Estimated cumulated incidence distributions for age-groups 1–4, 5–14, 15–24, 25–44 years during the second wave.

Mentions: Posterior distributions for the estimated cumulative incidence are shown in Figure 3 for the four age groups in the analysis. The accuracy of the estimate depends on the number of samples. Even in the 1–4 year age group where there is a limited number of samples (n = 274 over a 6 month period, Table 1), the distribution is relatively well localized. The estimated cumulative incidence is highest among 5–14 year olds with around 59% of individuals in this age group, representing some 3.5 million children, likely to have been infected in England in the second wave (Table 1). Children aged 1 to 4 years have the second highest cumulative incidence (49%) with 1.21 million likely infections. In the older age groups, cumulative incidence is still high (35% and 25% in the 15–24 and 25–44 year age groups respectively resulting in an estimated 2.4 and 3.7 million infections respectively. When compared with the number of clinical cases estimated by the HPA method in the second wave [6], the estimated number of infections were between 43 and 21 fold higher depending on the age group (Table 1).


Age-specific incidence of A/H1N1 2009 influenza infection in England from sequential antibody prevalence data using likelihood-based estimation.

Baguelin M, Hoschler K, Stanford E, Waight P, Hardelid P, Andrews N, Miller E - PLoS ONE (2011)

Posterior distribution of the cumulated incidences.Estimated cumulated incidence distributions for age-groups 1–4, 5–14, 15–24, 25–44 years during the second wave.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3044152&req=5

pone-0017074-g003: Posterior distribution of the cumulated incidences.Estimated cumulated incidence distributions for age-groups 1–4, 5–14, 15–24, 25–44 years during the second wave.
Mentions: Posterior distributions for the estimated cumulative incidence are shown in Figure 3 for the four age groups in the analysis. The accuracy of the estimate depends on the number of samples. Even in the 1–4 year age group where there is a limited number of samples (n = 274 over a 6 month period, Table 1), the distribution is relatively well localized. The estimated cumulative incidence is highest among 5–14 year olds with around 59% of individuals in this age group, representing some 3.5 million children, likely to have been infected in England in the second wave (Table 1). Children aged 1 to 4 years have the second highest cumulative incidence (49%) with 1.21 million likely infections. In the older age groups, cumulative incidence is still high (35% and 25% in the 15–24 and 25–44 year age groups respectively resulting in an estimated 2.4 and 3.7 million infections respectively. When compared with the number of clinical cases estimated by the HPA method in the second wave [6], the estimated number of infections were between 43 and 21 fold higher depending on the age group (Table 1).

Bottom Line: This method is applied to derive the cumulative and weekly incidence of A/H1N1 pandemic influenza in England during the second wave using sera taken between September 2009 and February 2010 in four age groups (1-4, 5-14, 15-24, 25-44 years).The highest cumulative incidence was in 5-14 year olds (59%, 95% credible interval (CI): 52%, 68%) followed by 1-4 year olds (49%, 95% CI: 38%, 61%), rates 20 and 40 times higher respectively than estimated from clinical surveillance.The method provides a more accurate and continuous measure of incidence than achieved by comparing prevalence in samples grouped by time period.

View Article: PubMed Central - PubMed

Affiliation: Immunisation, Hepatitis and Blood Safety Department, Health Protection Agency, London, United Kingdom. marc.baguelin@hpa.org.uk

ABSTRACT
Estimating the age-specific incidence of an emerging pathogen is essential for understanding its severity and transmission dynamics. This paper describes a statistical method that uses likelihoods to estimate incidence from sequential serological data. The method requires information on seroconversion intervals and allows integration of information on the temporal distribution of cases from clinical surveillance. Among a family of candidate incidences, a likelihood function is derived by reconstructing the change in seroprevalence from seroconversion following infection and comparing it with the observed sequence of positivity among the samples. This method is applied to derive the cumulative and weekly incidence of A/H1N1 pandemic influenza in England during the second wave using sera taken between September 2009 and February 2010 in four age groups (1-4, 5-14, 15-24, 25-44 years). The highest cumulative incidence was in 5-14 year olds (59%, 95% credible interval (CI): 52%, 68%) followed by 1-4 year olds (49%, 95% CI: 38%, 61%), rates 20 and 40 times higher respectively than estimated from clinical surveillance. The method provides a more accurate and continuous measure of incidence than achieved by comparing prevalence in samples grouped by time period.

Show MeSH
Related in: MedlinePlus