Global varicella vaccination programs

Abstract

Varicella (chickenpox) is an infectious disease caused by the highly contagious varicella zoster virus with a secondary attack rate greater than 90%. From this perspective, we aimed to establish the basis for a national varicella vaccine policy by reviewing vaccination programs and policies of countries that have introduced universal varicella vaccinations. As a result of the spread of varicella, an increasing number of countries are providing two-dose vaccinations and universally expanding their use. In practice, the efficacy and effectiveness of vaccination differ among vaccines and vaccination programs. Optimized vaccination strategies based on each country's local epidemiology and health resources are required. Accordingly, it is necessary to evaluate the effectiveness of varicella vaccines in different settings. Given the short-term and fragmented vaccine effectiveness evaluation in Korea, it is necessary to evaluate its effectiveness at the national level and determine its schedule based on the evidence generated through these studies.

A booster administration of the OKA/SK strain causes fatal disseminated varicella in an immunocompetent child

“…10,[13][14][15] A 22-year review also confirmed the overall safety profile of live attenuated varicella vaccines. 16 The purpose of this study was to develop a method to sequence the single-nucleotide polymorphism (SNP) loci unique to the most recently licensed live attenuated varicella vaccine largely only used in Korea and unrelated to vOKA strains used outside of Korea, and are independently derived from OKA/SK strain using MRC-5 cells as the cell strain, 17,18 to discriminate and identify the cause of fatal disseminated VZV infection in an immunocompetent child after booster immunization with the OKA/SK strain vaccine.…”

Study on Varicella-Zoster Virus Antibody Levels among Children Aged 1–7 Years in Changzhou, China

“…After the age of 4, children’s exposure to the outside world increases due to school attendance, and consequently, the chances of contracting VZV naturally increase significantly, and two doses of VarV would allow for at least 75% of children aged 4–7 years to have a protective level of antibodies. Furthermore, although the second dose of VarV has been shown to increase effectiveness significantly, the time between the two doses of vaccination is debated [ 34 ], e.g., short-interval two-dose varicella immunization schedules have been used in Germany [ 9 ], whereas long-interval varicella vaccination has been used in China and the U.S. Our results provided evidence for a long-interval vaccination strategy, with no breakthrough cases in the population, and suggested that two doses of vaccination had fair antibody persistence and ensured high protection until 7 years of age. In conclusion, a second dose of varicella vaccine is needed, and long intervals of varicella vaccination are feasible to improve protection against failure of the first dose and vaccine-induced immune decline.…”

“…For example, in the United States, the Advisory Committee on Immunization Practices (ACIP) approved a routine two-dose VarV schedule for children in 2006 [ 7 ]; the Government of Japan changed the VarV schedule from voluntary to routine vaccination in October 2014, in conjunction with the introduction of a two-dose VarV schedule [ 8 ]. There are still countries such as Australia, New Zealand, Argentina, and Oman that recommend a one-dose VarV schedule [ 9 ]. In addition, although several countries have adopted a two-dose VarV schedule, the timing of the second dose of vaccine varies.…”

“…In addition, although several countries have adopted a two-dose VarV schedule, the timing of the second dose of vaccine varies. Japan requires two doses of vaccine by 3 years of age (with an interval of at least 3 months) [ 8 ]; the United States requires a first dose of VarV at age 12–15 months and the second at 4–6 years [ 7 , 10 ]; and Germany recommends the first dose at 11–14 months and the second dose (with an interval of at least 1 month) at 15–23 months [ 9 ].…”

Expanded spectrum of varicella disease and the need for vaccination in India

“…4 So far, 44 countries have adopted either a partial or complete varicella vaccination schedule as part of their routine vaccination program. Of these countries, 29 have adopted a complete vaccination schedule by administering two doses of the varicella vaccine at an average age of 12 months for the first dose and 4–6 years old for the second dose 5 ( Table 1 ). No Asian country has adopted the vaccine as part of their routine vaccination program.…”