694 MMWR July 3, 2009
94% since 1997) (7). In this report, the significantly higher 4. CDC. Prevention of hepatitis A through active or passive immunization:
percentages in 2006 and 2007 of hepatitis A vaccination cov- recommendations of the Advisory Committee on Immunization Practices
(ACIP). MMWR 2006;55(No. RR-7).
erage among AI/AN and Hispanic children compared with 5. Smith PJ, Hoaglin DC, Battaglia MP, Khare M, Barker LE. Statistical
non-Hispanic white children likely reflect earlier emphasis methodology of the National Immunization Survey, 1994–2002. Vital
on these minority populations in areas with elevated rates of Health Stat 2 2005(138).
6. Selden TM. Compliance with well-child visit recommendations: evidence
hepatitis A and exemplify the substantial progress made toward from the Medical Expenditure Panel Survey, 2000–2002. Pediatrics
eliminating racial/ethnic disparities. 2006;118:e1766–78.
The findings in this report are subject to at least three limita- 7. CDC. Surveillance for acute viral hepatitis—United States, 2007. MMWR
tions. First, NIS is a landline telephone survey; although statis- 8. Bialek SR, Thoroughman DA, Hu D, et al. Hepatitis A incidence and
tical adjustments compensate for nonresponse and households hepatitis A vaccination among American Indians and Alaska Natives,
without telephones, some bias might remain. Second, NIS 1990–2001. Am J Public Health 2004;94:996–1001.
relies on provider-verified vaccination histories; incomplete 9. Bulkow LR, Wainwright RB, McMahon BJ, Middaugh JP, Jenkerson SA,
Margolis HS. Secular trends in hepatitis A virus infection among Alaska
records and reporting might result in biased estimates. Finally, Natives. J Infect Dis 1993;168:1017–20.
estimates for certain state and local areas with small sample
sizes and wide confidence intervals should be interpreted with
Studies have found that 97%–100% of children aged 2–18 Recurring Norovirus Outbreaks in
years had protective levels of antibody 1 month after receiving
their first dose of hepatitis A vaccine and 100% had protective a Long-Term Residential Treatment
levels 1 month after receiving their second dose (4). Although Facility — Oregon, 2007
current studies show long-term protection more than a decade On November 9, 2007, the Oregon Public Health Division
after vaccination, the second dose might be more important (OPHD) was notified of an outbreak of acute gastroenteritis
for lasting vaccine-induced immunity as younger children in a long-term residential treatment facility. Two previous
aged 12–23 months are vaccinated. Thus, for hepatitis A vac- outbreaks caused by norovirus had occurred at the facility in
cination to be effective, the vaccine must confer long-term March and July 2007. OPHD initiated an in-depth epide-
protection. miologic investigation, which included submitting archived
Continued surveillance and monitoring is critical because and recent specimens from the three outbreaks to CDC for