Antibodies against hepatitis viruses in merchant seamen

A Systematic Review for Vaccine-Preventable Diseases on Ships: Evidence for Cross-Border Transmission and for Pre-Employment Immunization Need

A literature review was conducted to identify evidence of cases and outbreaks of vaccine-preventable diseases (VPDs) that have been reported from on board ships and the methods applied on board for prevention and control, worldwide, in 1990 to April 2019. Moreover, evidence from seroprevalence studies for the same diseases were also included. The literature review was conducted according to Preferred Reporting Items for Systematic reviews (PRISMA) guidelines. A total of 1795 cases (115 outbreaks, 7 case reports) were identified, the majority were among crew (1466/1795, 81.7%) and were varicella cases (1497, 83.4%). The origin of crew cases was from sub-tropical countries in many reports. Measles (40 cases, 69% among crew), rubella (47, 88.7%), herpes zoster (9, 69.2%) and varicella cases (1316, 87.9%) were more frequent among crew. Mumps cases were equal among passengers and crew (22/22). Hepatitis A (73/92, 70.3%), meningococcal meningitis (16/29, 44.8%), and pertussis (9/9) were more frequent among passengers. Two outbreaks resulted in 262 secondary measles cases on land. Review results were used to draft a new chapter for prevention and control of VPDs in the European Manual for Hygiene Standards and Communicable Disease Surveillance on Passenger Ships. Despite past and current evidence for cross-border VPD transmission and maritime occupational risks, documented pre-employment examination of immune status, vaccination of seafarers, and travel advice to passengers are not yet regulated.

Hepatitis B and C infection in international travelers

BACKGROUND

Hepatitis B and C virus (HBV and HCV) cause significant morbidity and mortality worldwide. With the rise in international travel over the last three decades, many travelers are at risk of HBV and HCV infection.

METHODS

This review focuses on the epidemiology of HBV and HCV in international travelers, the modes of transmission, and the prevention of infection in travelers.

RESULTS

The risk of HBV and HCV infection varies widely and depends on the prevalence of the destination country, the duration of travel, and the activities undertaken while abroad. Travelers commonly undertake high-risk activities that place them at risk of both HBV and HCV infection. Poor uptake of preventative health measures and poor adherence to health recommendations are also common. The monthly incidence of HBV infection for long-term travelers to endemic countries ranges from 25 to 420 per 100,000 travelers. HBV infection can be prevented through timely vaccination of travelers. HBV vaccination is safe and efficacious with protective levels of antibodies achieved in >90% of recipients. Information regarding the risk of HCV acquisition is scarce and until recently was limited to case reports following medical interventions.

CONCLUSIONS

This review demonstrates international travelers are at risk of HBV and HCV infection and provides evidence-based information enabling health practitioners to provide more appropriate pre-travel advice. HBV vaccination should be considered in all travelers to countries with a moderate to high HBV prevalence (HBsAg ≥ 2%) and the risk and benefits discussed with the individuals in consultation with the health practitioner. There is no duration of travel without risk of HBV infection. However, it is apparent that those travelers with a longer duration of travel are at greatest risk of HBV infection (ie, expatriates). Travelers should also receive advice regarding the modes of transmission and the activities that place them at risk of both HBV and HCV infection.

Risk groups for hepatitis A virus infection

We report the conduct and results of a systematic search for evidence of risk of infection with hepatitis A virus (HAV) among blood transfusion recipients, travellers, the military, healthcare workers, sewage workers, foodhandlers, day care assistants, institutionalised subjects, blood transfusion recipients, drug addicts, homosexuals, prisoners and other risk groups such a liver transplantees. We report our recommendations for the use of the HAV vaccine in these groups.

Incidence and relative risk for hepatitis A, hepatitis B and tuberculosis and occurrence of malaria among merchant seamen

The purpose of the study was to assess the incidence and relative risk of hepatitis A and B and tuberculosis among Danish merchant seamen. We also assessed the occurrence of malaria. The study was based on record linkage of a research database containing data on 24,132 Danish male seamen and the Registry for Notifiable Infectious Diseases in Denmark, supplemented by data from other sources. The standardized incidence ratio (SIR) for hepatitis A for male seamen was 1.77 (0.91-3.10) as compared with the incidence in the general population. The incidence was 0.9 notified cases/10,000 years. The SIR for hepatitis B for male seamen was 3.02 (1.79-4.78), the main risk factors being intravenous drug use and casual sex abroad. Tuberculosis was not more common among seamen than in non-seamen. The results have implications for vaccination strategies in this occupational group. Malaria occurred frequently in the seamen, especially among those involved in West African trade. Irregular use of malaria prophylaxis and probably chloroquine resistance were of importance in some cases. To detect further cases of hepatitis A and B and malaria, other sources were reviewed. Only a few extra cases were identified. The registry of notifiable infectious diseases was thus found to be rather complete.