Assessment of Influenza Severity in Bhutan by Using WHO Framework Pandemic Influenza Severity Assessment (PISA): An

Tshering Dorji1, Kunzang Dorji1, Vishal Chettri2

  • 1National Influenza Centre (NIC), Royal Centre for Disease Control, Thimphu, Bhutan.

Insights

Bhutan established influenza severity thresholds using the WHO PISA framework. This allows for better preparedness against seasonal and pandemic influenza, especially for young children.

Area of Science:

  • Public Health
  • Epidemiology
  • Virology

Background:

  • Influenza poses a significant global health threat, causing millions of severe illnesses and hundreds of thousands of deaths annually.
  • Bhutan experiences high rates of influenza-associated hospitalizations, particularly in children under five, highlighting the need for enhanced surveillance and preparedness.

Purpose of the Study:

  • To assess influenza severity in Bhutan utilizing the World Health Organization's (WHO) Pandemic Influenza Severity Assessment (PISA) framework.
  • To establish national baseline and threshold values for influenza activity by integrating syndromic and influenza-specific data.

Main Methods:

  • The WHO Average Curve Method was used to determine seasonal and intensity thresholds for influenza.
  • Historical data from 2016-2019 and 2023 were analyzed to categorize influenza severity.

Main Results:

  • Influenza activity in Bhutan is nearly continuous, with two distinct annual peaks.
  • Thresholds for epidemic, moderate, high, and extraordinary levels of transmissibility and morbidity were defined.
  • The 2019 season showed the highest transmissibility and morbidity, with notable seasonal intensity variations.

Conclusions:

  • The PISA framework effectively assesses influenza severity in Bhutan, providing crucial data for public health decisions.
  • Established thresholds enhance preparedness for seasonal and pandemic influenza events.
  • Continuous adaptation of surveillance systems is vital for monitoring year-round influenza activity.
Abstract