A reduction in chronic hepatitis B virus infection prevalence among children in Vietnam demonstrates the importance of vaccination.

BACKGROUND: Vietnam has high endemic hepatitis B virus infection with >8% of adults estimated to have chronic infection. Hepatitis B vaccine was first introduced in the national childhood immunization program in 1997 in high-risk areas, expanded nationwide in 2002, and included birth dose vaccination in 2003. This survey aimed to assess the impact of Vietnam's vaccination programme by estimating the prevalence of hepatitis B surface antigen (HBsAg) among children born during 2000-2008. METHODS: This nationally representative cross-sectional survey sampled children based on a stratified three-stage cluster design. Demographic and vaccination data were collected along with a whole blood specimen that was collected and interpreted in the field with a point-of-care HBsAg test. RESULTS: A total of 6,949 children were included in the survey analyses. The overall HBsAg prevalence among surveyed children was 2.70% (95% confidence interval (CI): 2.20-3.30). However, HBsAg prevalence was significantly higher among children born in 2000-2003 (3.64%) compared to children born 2007-2008 (1.64%) (prevalence ratio (PR: 2.22, CI 1.55-3.18)). Among all children included in the survey, unadjusted HBsAg prevalence among children with ≥3 doses of hepatitis B vaccine including a birth dose (1.75%) was significantly lower than among children with ≥3 doses of hepatitis B vaccine but lacked a birth dose (2.98%) (PR: 1.71, CI: 1.00-2.91) and significantly lower than among unvaccinated children (3.47%) (PR: 1.99, CI: 1.15-3.45). Infants receiving hepatitis B vaccine >7 days after birth had significantly higher HBsAg prevalence (3.20%) than those vaccinated 0-1 day after birth (1.52%) (PR: 2.09, CI: 1.27-3.46). CONCLUSION: Childhood chronic HBV infection prevalence has been markedly reduced in Vietnam due to vaccination. Further strengthening of timely birth dose vaccination will be important for reducing chronic HBV infection prevalence of under 5 children to <1%, a national and Western Pacific regional hepatitis B control goal.

Adverse events following immunization (AEFI) with the novel influenza a (H1N1) 2009 vaccine: findings from the national registry of all vaccine recipients and AEFI and the passive surveillance system in South Korea.

This study characterized the adverse events following immunization (AEFI) with the novel influenza A (H1N1) 2009 vaccine in Korea. Data on immunization and AEFI were collected between October 27, 2009 and March 15, 2010 through the national immunization registry and passive surveillance systems. The frequency of AEFI and serious adverse events (SAEs) were calculated according to age, sex, priority group, and vaccine type. In 13,758,527 vaccine recipients aged 6 months or older, 2,530 AEFI were reported (18.4 per 100,000 immunizations). The AEFI reporting rate was highest among people aged 10-19 years (29.6 per 100,000 immunizations) and was higher in female recipients than in male recipients (20.0 versus 16.7 per 100,000 immunizations). Most AEFIs were nonspecific systematic reactions that occurred within 24 h (77.4%) after vaccine administration. A total of 178 vaccine-related SAEs were identified, and vaccine-related mortalities were not reported. This study showed that the AEFI reporting rate after influenza A (H1N1) 2009 vaccinations was relatively high, especially in the younger population. Mild systemic reactions accounted for the majority of reported AEFI, and fatal SAEs were rare. This study also implied that passive surveillance might be an efficient safety monitoring system that can detect relatively rare AEFI.

Implementing a national policy for hepatitis B birth dose vaccination in Philippines: lessons for improved delivery.

BACKGROUND: An estimated seven million Filipinos (10-12% of the population) are chronically infected with hepatitis B virus (HBV). Achieving high birth dose coverage with hepatitis B vaccine is critical for achieving the World Health Organization's Western Pacific Regional goal of reducing the prevalence of chronic HBV among children 5 years of age to <2% by 2012. METHODS: Seven months after the Philippines adopted a hepatitis B vaccine birth dose policy, hospitals with the highest number of deliveries were invited to participate in an assessment of implementation of the birth dose policy. Additionally, in metro Manila birth dose coverage was estimated before and after conducting a training workshop and supervisory follow-up for practitioners conducting home deliveries or deliveries at lying-in clinics. RESULTS: Of the country's largest 150 hospitals in terms of authorized bed capacity, 85 (56%) were included in this assessment. These hospitals had 55,719 deliveries during July-September 2007. Of these, 54% infants had a documented birth dose; however, only 22% were vaccinated within 24h of delivery. Having a copy of the hepatitis B vaccine vaccination policy (prevalence odds ratio [pOR]=4.7, 95% confidence interval [CI]=1.2-18.0), having standing orders pOR=4.8, 95% CI=1.3-18.1 and providing training pOR=18.9, 95% CI=5.3-67.0 were associated with >50% birth dose coverage in a hospital. In metro-Manila, regardless of place of birth, the training workshop and supervisory follow-up significantly improved hepatitis B vaccine administration within 24h after birth, increasing from 19% before to 74% after the training workshop and follow-up. CONCLUSIONS: Experience in the Philippines showed that actions by national, regional and health facility policy makers such as establishing national policies, distributing detailed and specific guidelines, conducting effective training and supervision, and having hospital standing orders substantially increased hepatitis B vaccine birth dose coverage.

Hepatitis A seroprevalence and risk factors among homeless adults in San Francisco: should homelessness be included in the risk-based strategy for vaccination?

OBJECTIVES: Homeless adults have an increased risk of infectious diseases due to sexual and drug-related behaviors and substandard living conditions. We investigated the prevalence and risk factors for presence of hepatitis A virus (HAV) antibodies among homeless and marginally housed adults. METHODS: We analyzed serologic and questionnaire data from a study of marginally housed and homeless adults in San Francisco from April 1999 to March 2000. We tested seroprevalance for total antibodies to HAV (anti-HAV) and analyzed data using Chi-square tests and logistic regression. RESULTS: Of the 1,138 adults in the study, 52% were anti-HAV positive. The anti-HAV prevalence in this study population was 58% higher than the expected prevalence based on age-specific prevalence rates from the general population. Number of years of homelessness (< or =1, 2-4, and > or =5 years) was associated with anti-HAV prevalence (46%, 50%, and 61%, respectively, p < 0.001). We found other differences in anti-HAV prevalence (p < 0.05) for ever having injected drugs (63% vs. 42% for non-injectors), being foreign-born (75% vs. 51% among U.S.-born), race/ethnicity (72%, 53%, and 45% for Hispanic, white, and black people, respectively), and increasing age (38%, 49%, and 62% among those aged <35, 35-45, and >45 years, respectively). These variables all remained significant in a multivariate model. CONCLUSIONS: We found overall anti-HAV prevalence elevated in this San Francisco homeless population compared with the general U.S. population. These data show that anti-HAV was associated with homelessness independent of other known risk factors, such as being foreign-born, race/ethnicity, and injection drug use. This increase indicates an excess risk of HAV infection and the potential need to offer hepatitis A vaccination as part of homeless services.

Physician practices regarding adult hepatitis B vaccination: a national survey.

BACKGROUND: Less than 50% of adults with risk factors for hepatitis B infection have been vaccinated. Although primary care settings typically serve an important role in immunization delivery, little is known about adult hepatitis B vaccination practices in primary care, including the use of strategies such as standing orders to improve immunization rates. The objectives of this study were to assess, among family physicians and general internists, current approaches to assessing adult patients for hepatitis B risk factors, reported hepatitis B vaccination practices, and attitudes about standing orders for hepatitis B vaccination. METHODS: From September to November 2006, a national sample of 433 family physicians and 420 general internists were surveyed. Results were analyzed in 2007 and 2008. RESULTS: Response rates were 65% for family physicians and 79% for general internists. Thirty-one percent of physicians reported assessing most or all adult patients for hepatitis B risk factors and vaccinating patients identified as high risk. Perceived barriers to hepatitis B vaccination included patients not disclosing high-risk behaviors, lack of adequate reimbursement for vaccination, and feeling too pressed for time to assess risk factors. Most surveyed physicians were very (47%) or somewhat (38%) supportive of using standing orders for hepatitis B vaccination in their practices. However, staff time constraints and patient unwillingness to disclose sensitive information to staff were perceived as barriers to using standing orders by a majority of respondents. CONCLUSIONS: In a national survey, less than one third of primary care physicians reported routinely assessing for and vaccinating adults with hepatitis B risk factors. This finding suggests that new strategies for adult hepatitis B vaccination in primary care settings are needed. Most physicians supported using standing orders for vaccination, but barriers were anticipated.

Hepatitis A vaccination coverage among adults aged 18-49 years in the United States.

BACKGROUND: Hepatitis A is the most common type of hepatitis reported in the United States. Prior to hepatitis A vaccine introduction in 1996, hepatitis A incidence followed a cyclic pattern with peak incidence occurring every 10-15 years. During 1980-1995, between 22,000 and 36,000 hepatitis A cases were reported annually. Since 1996, hepatitis A vaccination recommendations have included adults at risk for infection and children living in communities with the highest disease rates. This study provides the first national estimates of self-reported hepatitis A vaccination coverage among persons aged 18-49 years in the United States. METHODS: We analyzed the 2007 National Immunization Survey-Adult (NIS-Adult) data with restrictions to individuals aged 18-49 years. National estimates of hepatitis A vaccination coverage were calculated based on self-report and multivariable logistic regression analysis was used to identify factors independently associated with hepatitis A vaccination status. RESULTS: Among adults aged 18-49 years, 12.1% (95% confidence interval, CI=9.9-14.8%) had received two or more doses of hepatitis A vaccine in 2007. Hepatitis A vaccination coverage was significantly higher among adults aged 18-29 years (15.6%) and adults aged 30-39 years (12.9%) compared with adults aged 40-49 years (8.3%). Coverage was significantly lower for Hispanics (7.1%) compared with non-Hispanic whites (12.5%). Characteristics independently associated with a higher likelihood of hepatitis A vaccination among persons aged 18-49 years included younger age groups, persons at or above poverty level, persons with public medical insurance, and persons who received influenza vaccination in the past season. CONCLUSIONS: In 2007, self-reported hepatitis A vaccination coverage among adults aged 18-49 years was 12.1%. These data provide the first national hepatitis A vaccination coverage estimates among adults and are very important in planning and implementing strategies for increasing hepatitis A vaccination coverage among adults at risk for hepatitis A.

Prevalence of infection with hepatitis B and C viruses and co-infection with HIV in three jails: a case for viral hepatitis prevention in jails in the United States.

Hepatitis B vaccination and targeted testing for hepatitis C virus (HCV) are recommended for jails with medical services available. This study estimates hepatitis B virus (HBV) and HCV infection prevalence among jail inmates, since most previous studies have been conducted among prison inmates. Prison and jail populations differ: jails hold a wide spectrum of persons for an average of 10-20 days, including persons awaiting arraignment, trial, conviction, or sentencing, while prisons typically hold convicted criminals for at least 1 year. A stratified random sample of sera obtained during routine syphilis testing of inmates entering jails in Chicago (March-April 2000), Detroit (March-August 1999), and San Francisco (June 1999-December 2000) was tested for serologic markers of HBV and HCV infection. All sera had been previously tested for antibody to HIV (anti-HIV). A total of 1,292 serum samples (12% of new inmates) was tested. Antibody to HCV (anti-HCV) prevalence was 13%. Antibody to hepatitis B core antigen (anti-HBc) prevalence was 19%, and hepatitis B surface antigen (HBsAg) prevalence was 0.9%; 12% had serologic evidence of hepatitis B vaccination. Hispanics had high rates of chronic HBV infection (3.6% HBsAg positive) along with Asians (4.7% HBsAg positive). Among HIV-infected persons, 38% were anti-HCV positive and 8.2% were HBsAg positive. Anti-HBc positivity was associated with anti-HCV positivity (aOR=4.58), anti-HIV positivity (aOR=2.94), syphilis infection (aOR=2.10), and previous incarceration (aOR=1.78). Anti-HCV-positivity was associated with anti-HBc positivity (aOR=4.44), anti-HIV-positivity (aOR=2.51), and previous incarceration (aOR=2.90). Jail entrants had high levels of HCV and HBV infection and HIV co-infection; HBV prevalence was comparable to previous prison studies, and HCV prevalence was lower than prison studies. Hispanics had an unexpectedly high rate of chronic hepatitis B infection and had the lowest rate of hepatitis B vaccination. The finding that hepatitis B vaccination coverage among jail entrants is lower than the general population, despite this population's increased risk for infection, highlights the need to support vaccination in jail settings.

Survey of poliovirus antibodies during the final stage of polio eradication in Egypt.

BACKGROUND: Egypt provides ideal conditions for poliovirus (PV) transmission (high population density, high contact rates and low sanitation and hygiene in some areas). Despite excellent program performance, wild poliovirus type 1 (PV1) continue to circulate in 2004. To investigate potential causes for the persistence, we conducted a serological study. METHODS: Seroprevalence surveys were conducted in "polio-endemic" regions (Greater Cairo and Upper Egypt) and in one control region (Lower Egypt) in December 2004. Sera collected from infants aged 6-11 months were tested for antibodies to poliovirus by neutralization assay. RESULTS: A total of 973 subjects were tested. Seroprevalence to PV type 1 (PV1), PV type 2 (PV2) and PV type 3 (PV3) was 99, 99 and 91%, respectively. Significant variation in PV3 seroprevalence was found (range: 76-100%). Region, density, maternal education, socioeconomic status (SES), stunting and diarrhea were significant risk factors for lower seroprevalence in the univariate analysis. CONCLUSIONS: Our study suggested that uniformly high immunity levels (>96%) were required to interrupt PV1 transmission in the last remaining reservoirs (last PV1 was isolated in mid-January 2005 in Egypt). It further suggests substantial regional differences in OPV immunogenicity, with rural areas and low SES achieving the lowest seroprevalence to PV3.

Poliovirus vaccine shedding among persons with HIV in Abidjan, Cote d'Ivoire.

BACKGROUND: As polio eradication nears, the development of immunization policies for an era without the disease has become increasingly important. Outbreaks due to circulating vaccine-derived poliovirus (VDPV) and rare cases of immunodeficient persons with prolonged VDPV shedding lend to the growing consensus that oral poliovirus vaccine (OPV) use should be discontinued as soon after polio eradication as possible. The present study was conducted to assess whether persons infected with human immunodeficiency virus (HIV) experience prolonged VDPV shedding and serve as a source of reintroduction of virus into the population. METHODS: Adults infected with HIV had specimens tested (1) 8 months after a mass OPV campaign, to determine whether poliovirus related to OPV administered during the campaign was present (i.e., prolonged excretion), and (2) starting 7 weeks after a subsequent campaign, to determine whether poliovirus could be detected after the height of OPV exposure. RESULTS: A total of 419 participants were enrolled--315 during the 8-12 months after an OPV campaign held in 2001 and 104 during the 7-13 weeks after a 2002 campaign. No poliovirus was isolated from any participants. CONCLUSIONS: It appears unlikely that adults infected with HIV experience prolonged vaccine virus shedding, and, therefore, they probably represent a minimal risk of reintroducing vaccine virus into the population after poliovirus has been eradicated.