Single-Dose Vaccination: Approval Status and Country Adoption
Single-dose vaccination has been approved and implemented for hepatitis A in several countries, with Argentina being the most notable example of successful nationwide implementation. 1
Approved Single-Dose Vaccines
- Single-dose inactivated hepatitis A vaccines (including VAQTA, AVAXIM, HAVRIX, and EPAXAL) have shown high protective efficacy after just one dose 1
- Live attenuated hepatitis A vaccines are manufactured in China and used as a single dose in children as part of some national immunization programs 1
- Single-dose zoster (shingles) vaccine is recommended for adults aged 60 years or older regardless of prior herpes zoster episodes 1
Countries That Have Adopted Single-Dose Vaccination
Hepatitis A Single-Dose Programs
- Argentina: Implemented a universal one-dose hepatitis A immunization program in 2005 targeting children aged 12 months 1
- Russia: Military personnel have been vaccinated with single-dose AVAXIM with 90% seroprotection rates maintained for up to 5 years 1
- China: Uses single-dose live attenuated hepatitis A vaccines in children through national immunization programs 1
Evidence of Effectiveness
- Argentina's single-dose hepatitis A vaccination program resulted in an 88% decrease in hepatitis A incidence by 2007 (two years after implementation) 1
- Cases of hepatitis A virus-associated fulminant hepatic failure in Argentina decreased from 54% pre-immunization (1993-2005) to 27.7% post-immunization (2005-2008) 1
- Russian military personnel showed no cases of hepatitis A among vaccine recipients during 2002-2006 follow-up 1
Immunological Evidence Supporting Single-Dose Approach
- Studies across multiple countries (Switzerland, Nicaragua, USA, Argentina, Sweden) have demonstrated seroprotection rates of 80-92% at 12-36 months after a single dose of hepatitis A vaccine 1
- Protective anti-HAV antibody levels after a single dose of inactivated hepatitis A vaccine can persist for almost 11 years 1
- Evidence suggests no need for a booster dose of hepatitis A vaccine within at least 6 years of the initial dose 1
Economic and Implementation Benefits
- Single-dose vaccination schedules reduce barriers to vaccine implementation by:
- Cost-effectiveness modeling suggests that compared to no vaccination, one-dose hepatitis A vaccination in Argentina could save over US$15 million, while a two-dose schedule would save US$13.8 million 1
Challenges and Limitations
- Most vaccines are still officially licensed for multi-dose schedules despite evidence supporting single-dose efficacy 2, 3
- Additional research is needed on long-term cohorts vaccinated with single doses to guide future decisions on booster timing 1
- The cost-effectiveness of single-dose vaccination is highly dependent on country-specific disease endemicity levels 1
- Traditional vaccination schedules requiring multiple doses result in approximately 10 million infants remaining underimmunized globally each year 2
Other Vaccines Being Studied for Single-Dose Application
- Human Papillomavirus (HPV): Clinical trials are evaluating the efficacy of single-dose HPV vaccination compared to standard multi-dose regimens 4, 5
- Mathematical modeling suggests countries could achieve similar health benefits with single-dose HPV vaccination followed by potential two-dose mitigation strategies if needed 5
Practical Considerations for Implementation
- Single-dose vaccination programs benefit most from population census data and vaccination registries for monitoring effectiveness 6
- Monitoring vaccine effectiveness through periodic surveys of disease prevalence before and after vaccination introduction provides valuable real-world evidence 6
- Catch-up vaccination programs targeting older cohorts can minimize the interval between vaccination and the ability to monitor impact 6