Global Vaccine Safety

Vaccine Safety Net

VSN objective and general information

The objective of the Vaccine Safety Net is to facilitate the access of public health authorities, health professionals and the public to reliable information on vaccine safety via the internet.

Due to the success of immunization, some diseases are no longer perceived as a threat. Certain groups have even questioned the utility of vaccination in spite of its proven success in controlling disease. In recent years, a number of web sites providing unbalanced, misleading and alarming vaccine safety information have been established, which can lead to undue fears, particularly among parents and patients. Acknowledging the above-mentioned issues and urged by governments, key non-governmental organizations and the United Nations Children's Fund (UNICEF), WHO initiated, in 2003, the Vaccine Safety Net Project (VSN).

A key player in the Project is the Global Advisory Committee on Vaccine Safety (GACVS), established by WHO in 1999, to respond promptly, efficiently, and with scientific rigour to vaccine safety issues of potential global importance.

At the outset of the Project, GACVS developed four categories of criteria for good information practices - regarding credibility, content, accessibility and design to which sites providing information on vaccine safety should adhere. WHO evaluates websites for their adherence to these criteria.

GACVS criteria and website evaluation process

Throughout 2015, the VSN Working Group (WG) revised and updated the website evaluation criteria under the oversight of the GACVS. The WG also took into account feedback from a cross section of VSN members. The criteria were finalized and endorsed by GACVS on 17 September 2015. During this process VSN also formalized the procedure and criteria for screening VSN candidates.

Screening criteria


Inclusion criteria

The website:

  • Should have a public health focus.
  • May require member registration, but registration and information should be free of charge.
  • Contains information on vaccine safety and/or information on the safety of vaccines mentioned on the site.
  • Contains current evidence-based information.
  • Provides balanced information on vaccine safety issues (VSN defines balanced in the context of these criteria, as unbiased information that presents all reasonable sides of controversial issues in a fair way).
  • Should be professional: at a minimum, it should be clearly written and structured, and follow a logical hierarchy for ease of navigation.

Exclusion criteria

The following websites are not eligible to join the VSN:

  • Corporate websites.
  • Websites that are not reviewed regularly, e.g. no activity for 2+ years despite availability of new information.

Formal assessment criteria


WHO has prepared a companion document to assist VSN candidates and VSN members to adequately address each criterion. All of the criteria are listed in this document. The more complex criteria contain URLs pointing to examples and brief notes explaining what is expected.

VSN members are encouraged to undertake a careful review of their website to ensure its continuous compliance with the (revised) criteria for good information practices, and to complete any necessary changes by end of February 2016.

Translation into the remaining 5 UN languages (Arabic, Chinese, French, Russian and Spanish) has been initiated for both the revised criteria and the companion document. The translations will be posted on the WHO website as they become available.

VSN evaluation process


a. Evaluation of new websites

WHO is pleased to evaluate new candidates for inclusion in the VSN on a rolling basis. Please note that commercial sites are not evaluated or listed as a matter of policy.

The VSN evaluation process unfolds in the following manner:

  • If you feel that your site meets the GACVS criteria outlined above, kindly send a request for a site evaluation to gvsi@who.int
  • WHO will then conduct a preliminary assessment of your website. If your website meets the screening criteria then WHO will conduct a formal assessment.
  • During the formal assessment, your website will be evaluated against the revised criteria for good information practices by a team comprised of the VSN coordinator and one or more external consultants.
  • The evaluation team will send you feedback regarding any areas that require clarification or improvements in order to meet the GACVS criteria as well as a set of recommendations to assist you in meeting these criteria. When applicable, the WHO evaluation team will provide examples illustrating different ways that VSN members have addressed each recommendation.
  • Once the identified issues have been addressed to the satisfaction of the evaluators, WHO will add your web site to the list of VSN members.

b. Re-evaluation of VSN member websites

Re-evaluations are conducted every two years. The VSN evaluation process unfolds in the following manner:

  • The evaluation team will send the website focal point written notice that the website is due for re-evaluation.
  • The team will re-evaluate your website against the credibility and content criteria and send you feedback regarding any areas that require clarification or improvements in order to meet the GACVS criteria as well as a set of recommendations to assist you in meeting these criteria. When applicable, the WHO evaluation team will provide examples illustrating different ways that VSN members have addressed each recommendation.
  • When sites are considered by evaluators to satisfactorily meet credibility and content criteria, the date of finalization of the reevaluation is indicated at the bottom of the site description.

VSN members

The Vaccine Safety Net consists of a diverse group of websites that provide vaccine safety information in various languages. Each of these websites has been evaluated by WHO and meets the GACVS criteria for good information practices.

Sites that do not appear in the list may not yet have been reviewed, or they may be currently under review, or they may have been reviewed but do not meet the GACVS criteria for good information practices.

Last update:

10 November 2016 09:03 CET