Efficacy, safety, and formulation issues of the combined vaccines

ABSTRACT

Introduction: Controlling the preventable infectious diseases is the main goal of vaccination. Among the vaccines, combined vaccines are of great importance for their social, public health, and economic values. It is stated that the combined vaccines are as efficient and safe as the monovalent vaccines. However, a concern has raised about the efficacy and safety of the combined vaccines due to the outbreaks of vaccine-preventable diseases and occurrence of serious adverse events.

Areas covered: A retrospective literature search was conducted in the Google Scholar and PubMed databases to evaluate the efficacy and safety of the combined vaccines from 1980 to 2020 using appropriate keywords.

Expert opinion: Several studies have shown efficacy and safety issues related to the combined vaccines. Different factors contribute to the inefficacy and lack of safety in the vaccines including formulation problems, limited data in the pre-licensure studies and challenges related to imperfection of the post-licensure surveillance systems. For surmounting the mentioned obstacles, there is a need to provide new formulations of the vaccines, revise the vaccines҆ safety and efficacy acceptance standards in the pre-licensure studies, improvement of post-licensure surveillance systems, and education of healthcare staff.

KEYWORDS:

• AEFI
• combined vaccine
• DTaP
• DTwP
• efficacy
• formulation
• MMR
• safety
• vaccine hesitancy

Article highlights

• Outbreaks of the vaccine-preventable diseases and occurrence of serious adverse events highlight the need for evaluating the efficacy and safety issues of the combined vaccines.

• In some cases, studies have shown that DTP-based combined vaccines are not efficient and safe as the monovalent vaccines.

• Ignoring the efficacy and safety of the vaccines can lead to resurgence of the vaccine-preventable diseases.

• There is a need to increase the public trust and confidence regarding the vaccines and immunization and lowering the vaccine hesitancy, as well as a powerful collaboration of the vaccine manufacturers, national regulatory authorities, and public healthcare systems in order to prevent the outbreaks of the vaccine-preventable diseases.

Declaration of interest

The author confirms that he has no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript.

Reviewer disclosures

Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Disclaimer

The ideas and opinions expressed in this paper are those of the author (based on publicly available sources including published literatures and regulatory documents) and do not necessarily represent the official views of the Pasteur Institute of Iran as a vaccine manufacturer.

Additional information

Funding

This paper was not funded.