Pandemic influenza A vaccination and incidence of Guillain-Barré syndrome in Korea.
BACKGROUND
Many studies have investigated the association between Guillain-Barré syndrome (GBS) and vaccinations during the influenza A H1N1 pandemic of 2009 (pH1N1). Based on a nationally representative sample, we estimated the incidence of GBS during the pandemic period in Korea.


METHODS
All medical records of GBS cases were reviewed in 28 randomly selected hospitals during 2008-2010, and the number of GBS cases at the national level was extrapolated using emergency care utilization data. The GBS rate per 100,000 person-years was estimated in the reference and pandemic periods.


RESULTS
The incidence of GBS was 0.63 (95% CI: 0.37-0.89) per 100,000 person-years in the reference period and 0.87 (0.49-1.26) in the pandemic period. During the vaccination season, the pandemic period GBS incidence rate was not significantly higher than the reference period incidence rate (rate ratio: 1.52; 0.99-2.32), but difference was observed among persons aged 20-34 years. Rate of GBS increased after pH1N1 vaccination compared to the reference period (1.46, 1.26-1.68).


CONCLUSIONS
The incidence of GBS increased slightly but not significantly during the pandemic period, although pH1N1 vaccination increased the GBS rate. Therefore, mass influenza vaccination programs should not be precluded on the basis of GBS.
Department of Preventive Medicine, Yonsei University College of Medicine, Seoul, Republic of Korea.
Changsoo
C
Kim
Department of Pediatrics, CHA Bundang Medical Center, CHA University, Seongnam, Republic of Korea.
Seonkyeong
S
Rhie
National Cancer Center, Goyang, Republic of Korea.
Mina
M
Suh
Biostatistics Collaboration Unit, Yonsei University College of Medicine, Seoul, Republic of Korea.
Dae Ryong
DR
Kang
Health Insurance Review and Assessment Service, Seoul, Republic of Korea.
Yoon Jung
YJ
Choi
Korea Centers for Disease Control and Prevention, Osong, Republic of Korea.
Geun-Ryang
GR
Bae
Department of Neurology, Yonsei University College of Medicine, Gangnam Severance Hospital, Seoul, Republic of Korea.
Young-Chul
YC
Choi
Department of International Health Science, Graduate School of Public Health, Yonsei University, Seoul, Korea.
Byung Yool
BY
Jun
Department of Pediatrics, Severance Children's Hospital, Epilepsy Research Center, Yonsei University College of Medicine, Seoul, Republic of Korea. Electronic address: JOONSL96@yuhs.ac.
Joon Soo
JS
Lee
D000293:Adolescent; D000328:Adult; D000368:Aged; D005260:Female; D020275:Guillain-Barre Syndrome / Q000453:epidemiology* / Q000209:etiology*; D006801:Humans; D015994:Incidence; D053118:Influenza A Virus, H1N1 Subtype / Q000276:immunology*; D007252:Influenza Vaccines / Q000009:adverse effects*; D007251:Influenza, Human / Q000453:epidemiology* / Q000517:prevention & control; D008297:Male; D032541:Mass Vaccination / Q000009:adverse effects*; D008875:Middle Aged; D058873:Pandemics; D011159:Population Surveillance; D056910:Republic of Korea / Q000453:epidemiology; D055815:Young Adult
D007252:Influenza Vaccines
Guillain–Barré syndrome; Incidence rate; Influenza; Vaccination