Korean J Gastroenterol.  2012 May;59(5):360-365. 10.4166/kjg.2012.59.5.360.

Influenza A (H1N1) 2009 Pandemic Calm Down the Prevalence of Acute Hepatitis A in the Latter Half of 2009: Korean Population Study

• Byun JM
• Kim SG
• Zhang YY
• Kim YS
• Jeong SW
• Lee SH
• Jang JY
• Hong SJ
• Moon JH
• Kim HS
• Lee MS
• Kim BS

• KMID: 1792835
• DOI: http://doi.org/10.4166/kjg.2012.59.5.360

Abstract

BACKGROUND/AIMS
There was a spiking incidence of acute hepatitis A (AHA) in 2009 summer, but it went down drastically after an outbreak of influenza A (H1N1). We assessed the relationship between 2009 H1N1 pandemic and AHA prevalence from August to December 2009.
METHODS
We compared AHA cases nationwide and in our hospital for the period from the latter half of 2008 to the end of 2010. H1N1 cases in our hospital from August 2009 to December 2009 were included in the study and the correlation between 2009 H1N1 pandemic and AHA prevalence was assessed.
RESULTS
The national surveillance system reported 2,233, 7,895, 15,231 and 7,660 AHA cases from 2007 to 2010, respectively. A similar trend was noted in our hospital in the same periods. Although the national total incidence was increased in 2009, it showed steep decreasing trend line in the final 21 weeks of 2009 (weeks 32-52), as compared with 2008 and 2010. The mean weekly incidence percentage (AHA cases in a week/total in a year) in weeks 32-52 of 2009 was 1.17+/-0.55%, significantly lower than that in 2008 and 2010 (1.61+/-0.43% and 1.56+/-0.51%; p<0.001). Furthermore, we found a significant negative correlation between 2009 H1N1 pandemic and AHA in our hospital for weeks 32-52 of 2009 (r=-0.597; p<0.001).
CONCLUSIONS
The widespread occurrence of 2009 H1N1 pandemic highlighted the benefits of health care and good hygiene, such as effective hand washing and wearing of masks, which may have also interrupted hepatitis A virus transmission.

Keyword

Influenza A virus; H1N1 virus; 2009 H1N1 pandemic; Acute hepatitis A; Hepatitis A virus

MeSH Terms

Acute Disease
Hepatitis A/*epidemiology
Humans
Influenza A Virus, H1N1 Subtype/*isolation & purification
Influenza, Human/*epidemiology/virology
Pandemics
Prevalence
Republic of Korea/epidemiology
Seasons

Figure

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  Fig. 1 The incidence of novel influenza A (H1N1) by age at the Soon Chun Hyang University Bucheon Hospital during 2009. Approximately 80% of patients were <20 years old, and ~1% were >60 years old.

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  Fig. 2 Number of influenza A (H1N1)-positive patients at the Soon Chun Hyang University Bucheon Hospital in weeks 32-52 of 2009. The peak incidence was at weeks 43-44 (October) of 2009, and it has been falling since then.

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  Fig. 3 Acute hepatitis A (AHA) cases in Korea nationwide (A) and in the Soon Chun Hyang University Bucheon Hospital (B) during 2007-2010. The incidence of AHA in Korea has increased at an alarming rate in recent years (A). A similar trend was noted at the hospital in the same years (B).

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  Fig. 4 The incidence of acute hepatitis A (AHA) by age at the Soon Chun Hyang University Bucheon Hospital during 2009. The peak incidence was in those aged 30-39 years.

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  Fig. 5 Weekly acute hepatitis A (AHA) incidence percentage in the latter half of 2008, 2009 and 2010 in Korea. Although the total number of AHA cases was increased, during weeks 32-52 of 2009, the mean weekly incidence percentage (AHA cases in a week/total in a year) was significantly lower than that during the same period in 2008 and 2010.

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  Fig. 6 Correlation between 2009 influenza A (H1N1) infection and acute hepatitis A (AHA) at the Soon Chun Hyang University Bucheon Hospital for weeks 32-52 of 2009. A significant negative correlation between 2009 H1N1 pandemic and AHA was detected at the SCH hospital during surveillance weeks 32-52 in 2009 (r=-0.597; p<0.05).

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