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Category: Project

Description: The varicella zoster virus (VZV) infection typically leads to acute varicella, more commonly known as chickenpox, usually during childhood. After recovery from chickenpox, the virus enters a dormant state in the dorsal root ganglia. It can reactivate in about one third of the population later in life. The incidence of this latent varicella-zoster virus reactivation, known as herpes zoster (HZ), tends to increase with age or in situations where the immune system is compromised (1). Two vaccines, namely a live-attenuated VZV vaccine (Zostavax®), and an adjuvanted VZV glycoprotein E (gE) subunit vaccine (Shingrix®) have been approved for prevention of HZ. Other than HZ vaccination, vaccines against other common vaccine preventable infections or diseases such as influenza (annually), pneumococcal disease, and COVID-19 have been recommended for vulnerable individuals (2). However, the evidence regarding immunological responses and adverse events following the co-administration of vaccines in adults is limited. The majority of our understanding and evidence about this practice comes from studies conducted in children (3). In other words, the extent to which co-administration might impact immunogenicity and safety in adults has not been comprehensively investigated. As an example, a study in 2010 by MacIntyre et al. investigated the co-administration of the Zostavax® (Merck, live, attenuated VZV vaccine) with the 23-valent pneumococcal polysaccharide vaccine (PPSV23) (Pneumovax23) (4). Here they showed that the immunogenic response to the Zostavax® vaccine four weeks post vaccination was decreased. However, a study in 2018 by Bruxvoort et al. showed that there was no significant difference in the risk of getting infected in patients based on if vaccines were given simultaneously or separately (5). Nonetheless, there is a need to collect information and conduct investigations on the co-administration of HZ vaccines with other vaccines, such as those for influenza, COVID-19, hepatitis A and B, Haemophilus influenzae, and meningococcal diseases. Through this systematic review, we aim to describe the existing evidence regarding the immunogenicity and safety of HZ vaccines when co-administered with other vaccines. We aim to fill the knowledge gap regarding the safety and immunogenicity of co-administering herpes zoster vaccines with other vaccines in adults, with the goal of enhancing vaccination strategies and improving public health outcomes.