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Published on: August 3, 2010
Influenza A virus recycling revisited
1Task Force for Child Survival and Development, Decatur, GA 30030, USA.
Bulletin of the World Health Organization
|December 11, 1999
Summary
Influenza A virus subtype recycling is not supported by current data. While H2 influenza viruses should be monitored for pandemic preparedness, evidence does not suggest past subtype recycling events.
Area of Science:
- Virology
- Epidemiology
- Public Health
Background:
- Textbooks suggest influenza A virus subtypes (H2, H1, H3) recycle in humans, influencing pandemic predictions.
- The reappearance of H1 in 1977 has led some to consider H2 as the next potential pandemic strain.
Purpose of the Study:
- To review publications supporting the concept of influenza A virus subtype recycling.
- To evaluate the consistency of existing data with the proposed subtype recycling sequence.
Main Methods:
- Review of retrospective serological studies and seroarchaeology linking past pandemics to influenza A subtypes.
- Application of a validated pandemic seroarchaeological model to historical antibody data (H3, H2) in elderly populations.
- Comparison of findings with age-related excess mortality patterns during known influenza pandemics.
Main Results:
- Data supporting influenza A virus subtype recycling are inconsistent with the purported historical sequence.
- Seroarchaeology links H3 to the 1889-91 pandemic, not the 1900 pandemic as commonly cited.
- Pre-existing H2 antibodies in the elderly do not confirm H2 as a cause of late 1800s pandemics.
Conclusions:
- The concept of influenza A virus subtype recycling in humans is not supported by the reviewed evidence.
- While H2 influenza variants warrant inclusion in pandemic planning, it is not due to evidence of past recycling.
- Global surveillance remains critical for influenza preparedness, as the timing and subtype of future pandemics are unknown.
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