Computerised database monitors vaccine safety in Vietnam
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《英国医生杂志》
Officials in Vietnam have successfully set up a system to monitor vaccine related adverse events. The authors believe that it is the first purpose built health information system used to evaluate vaccine safety in a non-industrialised country (Bulletin of the World Health Organization 2005;83:604-8).
The government started a countrywide measles vaccination campaign in 2002 in the north of Vietnam that was extended to the south of the country in 2003. Parents and guardians of children aged 9 months to 10 years were invited to have their children immunised regardless of the child抯 measles vaccination history.
Vietnamese policy makers were concerned about the safety of the vaccine and the risk of adverse reactions, however. They wanted to make sure that the immunisation programme was adequately monitored.
They did this by issuing individuals with identification cards, based on census data, with a unique identity number for each household. Families were told to show the card whenever a child under 15 used the healthcare system. The surveillance system recorded all admissions to polyclinics or hospitals and diagnoses were coded according to guidelines. When no identification card was available trained data entry staff were able to conduct a computerised search of the census including name, sex, age, address, and the name of the head of household.
Using this method, 53 256 of the eligible 61 856 children (aged between 9 months and 10 years) were vaccinated with the measles vaccine, giving 86% coverage. Overall, 107 medical events were reported in the 14 days after the vaccination (relative risk 1.0, 95% confidence interval 0.8 to 1.3). However, 105 medical events were reported in the 14 days before the vaccination. The authors suggest that the 107 events reported after vaccination could be misinterpreted as being causally related to the vaccination.
A case series analysis among the cohort of children vaccinated during the mass vaccination campaign found no medical event to be significantly more frequent during the 14 days after measles vaccination than before it.
The authors suggest that expanded use of existing vaccines ?such as those for Japanese encephalitis and yellow fever - and the introduction of new vaccines may be short sighted in the absence of a health information system. Furthermore, they say, locally produced vaccine may not have to comply with the regulations that the international pharmaceutical industry is obliged to follow in industrialised countries.
"Further efforts should be made to establish health information systems to monitor vaccine safety in resource poor countries to enable a more complete understanding of vaccine safety, which is essential to maintain confidence in vaccine programmes," they write.
These systems are essential for monitoring potential adverse reactions to licensed vaccines, such as, say the authors. Such problems may go undetected unless there is an appropriate health database system, they argue.(BMJ Sun Tun)
The government started a countrywide measles vaccination campaign in 2002 in the north of Vietnam that was extended to the south of the country in 2003. Parents and guardians of children aged 9 months to 10 years were invited to have their children immunised regardless of the child抯 measles vaccination history.
Vietnamese policy makers were concerned about the safety of the vaccine and the risk of adverse reactions, however. They wanted to make sure that the immunisation programme was adequately monitored.
They did this by issuing individuals with identification cards, based on census data, with a unique identity number for each household. Families were told to show the card whenever a child under 15 used the healthcare system. The surveillance system recorded all admissions to polyclinics or hospitals and diagnoses were coded according to guidelines. When no identification card was available trained data entry staff were able to conduct a computerised search of the census including name, sex, age, address, and the name of the head of household.
Using this method, 53 256 of the eligible 61 856 children (aged between 9 months and 10 years) were vaccinated with the measles vaccine, giving 86% coverage. Overall, 107 medical events were reported in the 14 days after the vaccination (relative risk 1.0, 95% confidence interval 0.8 to 1.3). However, 105 medical events were reported in the 14 days before the vaccination. The authors suggest that the 107 events reported after vaccination could be misinterpreted as being causally related to the vaccination.
A case series analysis among the cohort of children vaccinated during the mass vaccination campaign found no medical event to be significantly more frequent during the 14 days after measles vaccination than before it.
The authors suggest that expanded use of existing vaccines ?such as those for Japanese encephalitis and yellow fever - and the introduction of new vaccines may be short sighted in the absence of a health information system. Furthermore, they say, locally produced vaccine may not have to comply with the regulations that the international pharmaceutical industry is obliged to follow in industrialised countries.
"Further efforts should be made to establish health information systems to monitor vaccine safety in resource poor countries to enable a more complete understanding of vaccine safety, which is essential to maintain confidence in vaccine programmes," they write.
These systems are essential for monitoring potential adverse reactions to licensed vaccines, such as, say the authors. Such problems may go undetected unless there is an appropriate health database system, they argue.(BMJ Sun Tun)