Varicella vaccination - the global experience

Abstract

Introduction Varicella, although a frequently benign childhood disease, nevertheless represents a considerable health burden. WHO recommends including varicella vaccines in universal routine vaccination programs, and maintaining coverage >80%. Many countries have successfully introduced varicella vaccination and have benefited from lower disease burden, but many others have not adopted the vaccine. Reasons include cost commitment for a ‘mild childhood disease’ or concerns that vaccination will shift varicella to older age groups or increase herpes zoster incidence. Areas covered This literature review summarizes the effectiveness and epidemiological impact of varicella immunization programs. Expert commentary Varicella vaccines are immunogenic with acceptable safety profiles. One and two dose schedules are highly effective against varicella and large reductions in disease incidence, particularly moderate-severe disease, have been widely reported. There is currently no evidence to suggest that the introduction of varicella vaccination results in a shift of varicella disease burden to older age groups. Although epidemiological studies have shown an increased incidence of herpes zoster since the vaccines were launched, there are many other contributing factors, and indeed, this secular trend was evident before their introduction. In conclusion, varicella vaccination easily fits into existing immunization programs and significantly reduces the often underestimated burden of varicella.

Differential uptake of herpes zoster vaccination associated with socioeconomic status: A population‐based study in Stockholm County, Sweden

“…The incidence of HZ in Sweden is around 3 per 1000 person years (for any HZ‐related diagnosis for all ages), which corresponds to around 6000 new cases in Stockholm County annually . The incidence gradually increases after the age of 50 years due to a decline in cell‐mediated immunity and has a peak in individuals over age 80 years …”

“…cell-mediated immunity and has a peak in individuals over age 80 years. 5,[8][9][10] In 2006, a live attenuated herpes zoster vaccine (HZV), Zostavax, was approved to prevent HZ and related post-herpetic neuralgia 11 and was subsequently available in Sweden from September 2013.…”

The clinical and economic burden of varicella in the Middle East: a systematic literature review

“…11 This fall in incidence observed in the Saudi Arabia study is in a similar range to that reported with other two-dose regimens. 6 Owing to a lack of published data from the Middle East in the post-UVV era, it is difficult to gain insight into the impact of UVV programs on hard outcomes such as mortality, complication rates, and hospitalization rates in this area. In Turkey, the proportion of children hospitalized with varicella was higher in unvaccinated compared with vaccinated children (0.6% vs 0.2%).…”

“…5 There are numerous global and regional reviews that discuss the epidemiology of varicella and the impact of vaccination programs on incidence, herd immunity, morbidity, and mortality. [6][7][8] However, very little has been published for the Middle East; a recent review by Al-Turab et al provides a general overview of varicella infection in the Middle East with a specific focus on seroprevalence. 9 This review highlighted that, as in most countries, varicella is a childhood disease with seropositivity to varicella increasing with age.…”

Human herpesvirus portal proteins: Structure, function, and antiviral prospects

“…Latent VZV may reactivate to cause herpes zoster (“shingles”) presenting as an asymmetrical dermatomal rash and accompanied by post herpetic neuralgia . Vaccines are available to prevent chickenpox and ease the burden of zoster . Valacyclovir can reduce time to healing of lesions, but additional therapeutics are sought with improved efficacy for zoster/PHN 116 and to treat rare cases of drug resistant VZV …”