Seroprevalence and risk factors of hepatitis B and C virus infections in female workers of Lao garment factories

<div><p>The prevalence of hepatitis B and C virus infections may be higher in vulnerable populations or in individuals likely to be exposed through risk behaviors such as female garment factory workers in Lao People’s Democratic Republic. A cross-sectional study was performed on 400 female garment workers in Vientiane Capital. Women were tested for hepatitis B virus surface antigen and antibodies against hepatitis B core, surface antigen and hepatitis C virus using commercial Enzyme-linked immuno-absorbent assays. Participants completed a standardized questionnaire about potential risk factors for both infections. Sixteen women (4±1.9%) were HBsAg carriers, 187 (47%) had anti-HBc, 116 (29%) anti-HBs and 7 (1.8±1.3%) anti-HCV antibodies. Three factors were significantly associated with the presence of anti-HBc (indicating previous exposure to HBV): (i) residence in dormitories, (ii) more than one sexual partner, (iii) history of abortion. Despite a high risk of exposure, the prevalence of anti HBV and anti HCV infection markers in this sample of female workers was not higher than in the Lao general population. Our data suggest that exposure to HBV happens later during life and was significantly associated with sexual risk behavior. Thus, this study highlights the vulnerability of these women who were mostly young, uneducated, unvaccinated, of rural origin and were not aware of the risk of infections. An occupational health program targeting the female factory workers should be implemented in Lao PDR.</p></div

Association between socio-demographic characteristics, knowledge and risk factors with Anti-HBc.

<p>Ref = reference.</p

Serological markers of hepatitis B and C.

<p>Serological markers of hepatitis B and C.</p

Diphtheria in Lao PDR: Insufficient Coverage or Ineffective Vaccine?

<div><p>Background</p><p>During late 2012 and early 2013 several outbreaks of diphthe-ria were notified in the North of the Lao People’s Democratic Republic. The aim of this study was to determine whether the re-emergence of this vaccine-preventable disease was due to insufficient vaccination coverage or reduction of vaccine effectiveness within the affected regions.</p><p>Methods</p><p>A serosurvey was conducted in the Huaphan Province on a cluster sampling of 132 children aged 12–59 months. Serum samples, socio-demographic data, nutri-tional status and vaccination history were collected when available. Anti-diphtheria and anti-tetanus IgG antibody levels were measured by ELISA.</p><p>Results</p><p>Overall, 63.6% of participants had detectable diphtheria antibodies and 71.2% tetanus antibodies. Factors independently associated with non-vaccination against diphtheria were the distance from the health centre (OR: 6.35 [95% CI: 1.4–28.8], p = 0.01), the Lao Theung ethnicity (OR: 12.2 [95% CI:1,74–85, 4], p = 0.01) and the lack of advice on vac-cination given at birth (OR: 9.8 [95% CI: 1.5–63.8], (p = 0.01) while the level of maternal edu-cation was a protective factor (OR: 0.08 [95% CI: 0.008–0.81], p = 0.03). Most respondents claimed financial difficulties as the main reason for non-vaccination. Out of 55 children whose vaccination certificates stated that they were given all 3 doses of diphtheria-containing vaccine, 83.6% had diphtheria antibodies and 92.7% had tetanus antibodies. Furthermore, despite a high prevalence of stunted and underweight children (53% and 25.8%, respectively), the low levels of anti-diphtheria antibodies were not correlated to the nutritional status.</p><p>Conclusions</p><p>Our data highlight a significant deficit in both the vaccination coverage and diphtheria vaccine effectiveness within the Huaphan Province. Technical defi-ciencies in the methods of storage and distribution of vaccines as well as unreliability of vac-cination cards are discussed. Several hypotheses are advanced to explain such a decline in immunity against diphtheria and recommendations are provided to prevent future outbreaks.</p></div

Anti-diphtheria and anti-tetanus antibody seroprevalence in children from villages less than or greater than 100 minutes travel from health centres (n = 132; mns = minutes; *p = 0.02, **p<0.001).

<p>Anti-diphtheria and anti-tetanus antibody seroprevalence in children from villages less than or greater than 100 minutes travel from health centres (n = 132; mns = minutes; *p = 0.02, **p<0.001).</p

Expanded Programme on Immunization schedule, Lao PDR.

<p>BCG: Bacillus Calmette-Guérin; DTP: Diphtheria, Tetanus, Pertussis; Hib: <i>Haemophilus influenzae</i> b; HepB: Hepatitis B; OPV: oral polio vaccine</p><p>* Pentavalent vaccine (HepB included since October 2009).</p><p>**Rubella included since 2012.</p><p>Expanded Programme on Immunization schedule, Lao PDR.</p

Socio-demographic characteristics of children.

<p>*NS = not significant (p ≥ 0.05)</p><p>**Lao kips (8000 LAK worth one US dollar).</p><p>Socio-demographic characteristics of children.</p

Seroprevalence of diphtheria and tetanus antibodies according the nutritional status of children.

<p>W/H ratio: weight-for-height ratio; MUAC: Middle Upper Arm Circumference.</p><p>Seroprevalence of diphtheria and tetanus antibodies according the nutritional status of children.</p

Vaccination status of children according to the source of information.

<p>BCG: Bacillus Calmette-Guérin; HepB: Hepatitis B; DTP: Diphtheria, Tetanus, Pertussis; Hib: <i>Haemophilus influenzae</i> b.</p><p>Vaccination status of children according to the source of information.</p

Near and remote village vaccination history according to yellow cards and interview (n = 132; mns = minutes; *p<0.05).

<p>Near and remote village vaccination history according to yellow cards and interview (n = 132; mns = minutes; *p<0.05).</p