South-East Asia Regional Conference on Epidemiology

Preparing Indonesia for pandemic influenza
I Nyoman Kandun and Nyoman Kumara Rai
Over the last 100 years, the incidence of influenza in Indonesia has been studied through a variety
of surveys and sentinel surveillance activities (1,2). Influenza is not a nationally notifiable disease in
Indonesia, as it is generally perceived to be a mild self-limiting illness among the general public and,
to some extent, by the medical profession as well.
Although there is limited information available about the relative importance of influenza in
contributing to epidemic and sporadic disease, understanding the epidemiology of influenza viruses
is important to document the potential burden of the disease, compared with that of other respiratory
illnesses such as bacterial pneumonia (3). Surveillance activities can provide useful baseline data
for measuring local epidemics and can generate critical information regarding the circulating strains
that could have an impact on the annual selection of appropriate vaccine strains. This is especially
important to aid in the use of vaccines for the target population of yearly hajj pilgrims from Indonesia
to Saudi Arabia (4,5).
Influenza surveillance
The National Institutes of Health Research and Development (NIHRD) started to conduct influenza
surveys in 1975 (2). The surveys stopped and re-started several times as influenza was not perceived
to be a priority, but were re-started in 1999. The aim of the surveys was to estimate the burden of
influenza in the country.
Specifically, the objectives were:
• To identify the characteristics of influenza-like illness (ILI) cases;
• To identify the types and subtypes of the influenza virus in Indonesia;
• To form a national influenza network.
The surveys are conducted in 48 sites comprising both hospitals and health care centres in a total
of 22 provinces (1). Even though these surveys do not cover or fully represent the entire Indonesian
population, they offer an opportunity to assess within-country variation in disease trends. This is
especially important for a country of Indonesia’s geographical expanse and population size. The
survey findings suggest that influenza viruses circulate throughout the year. Between 2006 and 2008,
there was a high prevalence of influenza A in the rainy season (December to February) and flu B had
a consistent low prevalence throughout the year. During these surveys, influenza was detected in 20%
of ILI cases where approximately 4000 entered the survey population each year. Future surveys will
need to relate laboratory results with clinical outcomes as well as understand the age distribution and
other demographic characteristics of those infected.