Varicella vaccination: a laboured take-off.

Area of Science:

• Immunology and Epidemiology
• Vaccinology
• Public Health

Background:

• Varicella vaccines are highly immunogenic, efficacious, and safe for preventing varicella disease.
• Universal varicella vaccination is recommended in the USA, but its use is heterogeneous across European Union/European Economic Area countries.
• Diverse vaccine recommendations are driven by uncertainties regarding the impact of varicella vaccination on varicella and herpes zoster epidemiology.

Purpose of the Study:

• To address uncertainties surrounding the epidemiological impact of varicella vaccination.
• To highlight the need for improved surveillance systems and mathematical modeling for assessing vaccine effects.
• To emphasize the requirement for a better understanding of herpes zoster risk factors.

Main Methods:

• Review of existing vaccination recommendations and epidemiological data.
• Discussion of the utility and limitations of surveillance systems and mathematical models.
• Identification of knowledge gaps in understanding vaccine impact on disease epidemiology.

Main Results:

• Significant variability exists in varicella vaccine recommendations across European countries.
• Lack of comprehensive and standardized surveillance for varicella and herpes zoster hinders effect assessment.
• Mathematical models, while useful, require careful interpretation due to underlying assumptions.

Conclusions:

• Continuous and robust surveillance of varicella and herpes zoster is crucial for evaluating vaccination program impacts.
• Further research into herpes zoster risk factors is needed.
• Enhanced data collection and analysis are essential to clarify the long-term epidemiological effects of varicella vaccination.