The two pronged consequences of VZV have been previously discussed in Chapter 3. In brief, childhood chickenpox is one manifestation of VZV. Children develop immunity to the latent virus. The major risk after this event is that one’s immunity will wane over time and the VZV reactivates, caus- ing painful shingles. As one ages, the probability that the VZV will reactivate approaches 50% for those 85 and older. There are numerous major beneﬁts from the VZV or “chickenpox” vaccine:
1. Prevention of chickenpox in young children.
2. As widespread immunization occurs, there will be a reduced reservoir for the wild virus.
3. Reduction in infant hydrocephaly associated with maternal VZV infection early in pregnancy (234).
4. Vaccination in the elderly to attenuate the course of herpes zoster (235,236).
5. Vaccination of others whose immune systems are impaired (236).
It is evident that waning cellular immunity is strongly correlated with the development of herpes zoster (237–239). The live attenuated varicella vaccine was approved for anyone aged 1 year or older by the FDA in 1995. The vaccine was developed in Japan over 30 years ago, yet the United States is the only country using it as a universal vaccine against chick- enpox. Cases of chickenpox and complications from chicken- pox (hospitalizations) have been reduced. Children usually receive 1 dose of vaccine, while those 13 years of age or older receive 2 doses 1–2 months apart.
One issue has been the degree of efﬁcacy of the vaccine. Breakthrough varicella is reported in 10–15% of vaccinees. Vaccine effectiveness, based on case studies and clinical tri- als, may range from <45–90% (240). Another issue has been the lasting degree of high immunity. Vaccine efﬁcacy seems to be reduced by improper handling and storage of the vaccine and individual response characteristics, such as a history of asthma or age of <14 months at time of immunization, and
short interval (<30 days) between MMR inoculation and VZV immunization. Efﬁcacy may be improved by adminis- tering a higher dosage of vaccine and/or more than one dose in children. When older children (>13 years of age) and adults are given two doses of VZV vaccine, higher antibody titers are evident 6 weeks after immunization. In small chil- dren, higher antibody titers occur when a booster dose is given (241).
Vaccination with the Oka or vaccine strain of VZV rarely causes rash. Breakthrough cases due to wild virus tend to be less severe than cases in the non-vaccinated. Breakthrough cases are less likely to cause secondary infection (241).
Investigators are currently evaluating the potential for the live-attenuated vaccine to act as a booster for the compro- mised cellular immune response in older individuals. A phase III clinical trial is underway to investigate this effect and to determine any clinical signiﬁcance with regard to the reduc- tion of severity or prevention of herpes zoster. The vaccine under investigation is a more potent version of the one cur- rently licensed for immunization in children.
In later life, VZV plagues the elderly as painful shingles. Especially painful are those that occur on the face and involve the trigeminal nerve. Levin et al. (242) have previ- ously studied the immune response of elderly persons who received the live attenuated vaccine and found that approxi- mately 10–15% of the vaccinees failed to develop increased immunity. Overall, the calculated half-life of the enhanced immunity in this study was 54 months. The long-term dura- tion of the booster effect had a positive correlation with the dose of the administered vaccine. In a follow-up study 6 years after vaccination, Levin et al. (243) found that the varicella- zoster virus-responding T cell frequency was still signiﬁcantly improved over initial baseline measurements, as well as expected measurements for this age cohort. In this vaccinated population, the frequency of herpes zoster was within the range of expected incident for this age cohort. However, in all cases of herpes zoster in the study, the number of lesions was small, the associated pain was minimal, and postherpetic neuralgia did not occur. This preliminary study suggests that
vaccination in the elderly may be able to attenuate the course of herpes zoster (235).
Fever. Fever is common (37.7°C or 100°F), but a fever over 39°C (102°F) may be of more concern. Patients should check with their physician.
Injection site. The injection site may be tender or erythematous but this should diminish over 2–3 days. Varicella-like rash. Patients should check with their doctor if a rash appears in areas other than the injec-
These signs and symptoms are less common, but patients should check with their doctor if they continue for an extended period of time or are more bothersome than usual:
Common cold or sore throat. Congestion or cough.
Nausea or diarrhea. Rare events.
• Black, tarry stools
• Blood in urine or stools
• Reddening of skin, especially around the ears
• Airway or swallowing difﬁculty
• Peripheral itching
(feet or hands)
• Unusual bleeding or bruising
• Sudden or severe tiredness or weakness
• Muscle or joint pain
• Pinpoint red macules on skin
• Stiff neck
• Severe or continuing headache
• Facial swelling (eyelids, face, or nasal passage ways, swollen glands)
• Patients should check with their doctor as
soon as possible if any of these rare events occurs.
Leukemia. Immunized children with leukemia are less likely to develop chickenpox or shingles.
Allergies to neomycin or gelatin. May be contraindi- cated for vaccine administration.
Pregnancy or intent to become pregnant. Varicella vaccine is not known to harm the fetus, but tests have not been done. However, wild viral infection can some- times cause birth defects.
Breastfeeding. Mothers who receive the vaccine and wish to breastfeed should consult ﬁrst with their doctor. Tuberculosis. Although wild virus infection may exacer- bate tuberculosis, there are no reports that the vaccine
causes tuberculosis to worsen.
Immune deﬁciency. Decreased immunity may increase the chance and degree of side effects of the vaccine and/ or decrease the efﬁcacy of the vaccine.
Febrile illness. Febrile illness symptoms may be con- fused with possible side effects of the vaccine.