In 2012, KSID recommended to inoculate herpes zoster vaccine to adults over 60 without contraindication but the recommendation for adults at 50 through 59 was deferred, saying that they could be vaccinated [4
]. It was because the clinical efficacy of the herpes zoster vaccine on the population from 50 to 59 could not be verified from the dimension of association as the result of ZEST study was not officially published, although Korea Food and Drug Administration lowered the age to use ZOSTAVAX to 50 in July, 2011.
In chronic disease patients and the immune-compromised, the risk of incidence of herpes zoster increases but herpes zoster vaccination is not recommended under the specific age even though they have an immune deficiency disease because the recommendation criteria were set by age. It is because there are not sufficient research results regarding the safety and usefulness of herpes zoster vaccine in the immune-compromised. If reliable results are made in the follow-up studies regarding the usefulness of herpes zoster vaccine in the immune-compromised, there is possibility that herpes zoster vaccine can be recommended to the population with lower age.
There are some different opinions regarding the necessity of herpes zoster vaccine to those who have past history of herpes zoster. US Center for Disease Control and Prevention (US CDC) recommended to inoculate herpes zoster vaccine regardless of past history of herpes zoster, because there is risk of recurrence although it is rare, because it is not clear up to when the incidence risk is reduced, and because there is possibility that the patient does not know about the past disease history. In a study which evaluated the safety and the immunogenicity of ZOSTAVAX on those who were over 50 in 2010, there were no major reactions when ZOSTAVAX was inoculated to those who had herpes zoster in the past, and other local or systemic reactions were similar to the results of SPS [17
]. Additionally, the antibody titer measured 4 weeks after the vaccination, those who had ZOSTAVAX showed 2.1 times higher before the vaccination and 2.07 times higher than those who had placebo. It seems that the study results supported the recommendation of US CDC. In a cohort study performed on those who had herpes zoster within two years to evaluate the recurrence risk of herpes zoster, however, herpes zoster recurrence rate was low regardless of the inoculation of ZOSTAVAX, which can be interpreted that ZOSTAVAX vaccination may not be necessary for those who had past history of herpes zoster [18
In SPS, the safety was evaluated on 21,000 people and a sub-study was performed that asked 3,345 vaccine group and 3,271 placebo group to record reactions on vaccination report card (VRC) up to 42 days after vaccination [2
]. In the study, both groups showed major reaction rate as 1.4%, while in the evaluation through VRC, vaccine group showed relatively higher major reaction rate (1.9% vs. 4.9%). Major reactions which were judged to be related with herpes zoster vaccine were found in 2 subjects, which were attack of asthma and poly-myalgia rheumatic respectively. The most common reaction after the vaccination was redness, pain, swelling, pruritus, and hematoma in the injection site, and headache was the most common systemic reaction. Most of reactions were minor and slight and they disappeared within days automatically. Although there were a few reports regarding zoster-like eruption after vaccination, only wild type VZV was identified and no case was diagnosed as eruption by Oka/Merk strain. When varicella-like eruption occurs after vaccination, they are sensitive to VZV and virus can be spread through them. Therefore, it is necessary to take care not to contact those who do not have of evidence of varicella immunity if they have skin lesions such as eruption after vaccination. The aspects and frequency of reactions reported in ZEST study were similar to the results of SPS [16
Precautions to vaccination
The aged tend to be in immune deficiency because of diseases such as cancers or to have anti-cancer drugs or immune-suppressants. As the currently licensed herpes zoster vaccine is a live-attenuated vaccine, those who have severe immune deficiency diseases or use immune-suppressants should not have herpes zoster vaccination. However, those who have not had anti-cancer treatment or radiotherapy for at least 3 months because of leukemia in the state of remission, those who have local/inhaled steroid or low does systemic steroid, those who have steroid as an alternative medicine for adrenal insufficiency, and those who have low dose immunosuppressant (less than 0.4 mg/kg/wk of methotrexate, 3.0 mg/kg/day of azathioprine, and 1.5 mg/kg/day of 6-mercaptopurine) are exempted from the contraindication.
As materials regarding the safety and efficacy of herpes zoster vaccination while recombinant human immune control agents (adalimumab, infliximab oretanercept) were being used, it is desirable to be vaccinated before the administration of these drugs or 1 month after the completion of the administration. It is desirable for those who use antiviral agents such as acyclovir, famciclovir, valacyclovir to have herpes zoster vaccination at least 24 hours after the completion of the administration, as such agents can affect the proliferation of virus.
Like most other vaccines, herpes zoster vaccine does not show significant difference in effects or reactions even when it is vaccinated with other vaccines such as influenza vaccine. However, in the product manual of herpes zoster vaccine, it is recommended to have 23-valent pneumococcal polysaccharide vaccine (PPV23) vaccination to have 1 month interval. It is because there was a report that concurrent vaccination of herpes zoster vaccine and PPV23 may reduce immunogenicity [19
]. However, in later study results, it was reported that there was no difference in efficacy even when herpes zoster vaccine and PPV23 were vaccinated at the same time [20
] and US CDC announced that there would be no problem even they were inoculated concurrently.