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Estimating the prevalence of infectious diseases from under-reported age-dependent compulsorily notification
Marcos Amaku1, Marcelo Nascimento Burattini1,2, Eleazar Chaib1
1LIM01-Hospital de Clínicas, Faculdade de Medicina Universidade de São Paulo, São Paulo, SP, Brazil.
Background:
National or local laws, norms or regulations (sometimes and in some countries) require medical providers to report notifiable diseases to public health authorities. Reporting, however, is almost always incomplete. This is due to a variety of reasons, ranging from not recognizing the diseased to failures in the technical or administrative steps leading to the final official register in the disease notification system. The reported fraction varies from 9 to 99% and is strongly associated with the disease being reported.
Methods:
In this paper we propose a method to approximately estimate the full prevalence (and any other variable or parameter related to transmission intensity) of infectious diseases. The model assumes incomplete notification of incidence and allows the estimation of the non-notified number of infections and it is illustrated by the case of hepatitis C in Brazil. The method has the advantage that it can be corrected iteratively by comparing its findings with empirical results.
Results:
The application of the model for the case of hepatitis C in Brazil resulted in a prevalence of notified cases that varied between 163,902 and 169,382 cases; a prevalence of non-notified cases that varied between 1,433,638 and 1,446,771; and a total prevalence of infections that varied between 1,597,540 and 1,616,153 cases.
Conclusions:
We conclude that the model proposed can be useful for estimation of the actual magnitude of endemic states of infectious diseases, particularly for those where the number of notified cases is only the tip of the iceberg. In addition, the method can be applied to other situations, such as the well-known underreported incidence of criminality (for example rape), among others.
Insights
This study introduces a new method to estimate the true prevalence of infectious diseases, accounting for incomplete disease reporting. The model successfully estimated underreported hepatitis C cases in Brazil, highlighting its utility for public health surveillance.
Area of Science:
- Epidemiology
- Public Health
- Mathematical Modeling
Background:
- Disease notification systems are mandated by law but often suffer from incomplete reporting due to various factors.
- The fraction of reported cases can vary significantly (9-99%), impacting accurate disease prevalence assessment.
- Underreporting is a common challenge in tracking infectious diseases and other public health issues.
Purpose of the Study:
- To propose a novel statistical method for estimating the full prevalence of infectious diseases, addressing incomplete notification.
- To quantify the number of non-notified infections and improve the accuracy of disease transmission intensity parameters.
- To demonstrate the method's applicability using the case of hepatitis C in Brazil.
Main Methods:
- Developed a mathematical model that assumes incomplete incidence notification.
- The model estimates the number of non-notified infections.
- The method allows for iterative correction by comparing results with empirical data.
Main Results:
- Applied to hepatitis C in Brazil, the model estimated a total infection prevalence between 1,597,540 and 1,616,153 cases.
- Notified hepatitis C cases ranged from 163,902 to 169,382.
- Non-notified hepatitis C cases were estimated between 1,433,638 and 1,446,771.
Conclusions:
- The proposed model effectively estimates the true magnitude of endemic infectious diseases, especially when reported cases are only a fraction of the total.
- This methodology can be valuable for public health surveillance and policy-making.
- The approach has potential applications beyond infectious diseases, including underreported crime statistics.
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