What procedural change does AO No. 2018-0013 advocate for during vaccine shortages?

AO No. 2018-0013 advocates for the use of vaccines that meet certain quality standards, and specifically emphasizes the importance of utilizing only WHO-prequalified vaccines during times of vaccine shortages. The rationale behind this advocacy is to ensure that despite limitations in availability, patient safety and vaccine efficacy remain paramount. WHO prequalification indicates that a vaccine has undergone rigorous evaluations and meets specific international standards, thus offering assurance regarding its quality, safety, and efficacy for public health use.

In the context of the other options, using expired vaccines, non-FDA approved vaccines, or non-WHO prequalified vaccines would compromise patient safety and public trust in vaccination programs. These alternatives do not adhere to the necessary safety and regulatory standards that ensure effective immunization, which is why they are not supported in the procedural change advocated by the AO 2018-0013.