Standardized immunological assays for assessing COVID-19 vaccines by the CEPI-Centralized Laboratory Network

Abstract

The CEPI Centralized Laboratory Network implemented key steps in the transfer and monitoring of the developed immunological SARS-CoV-2 assays to ensure standardization across all the facilities of the network. This comprehensive evaluation reinforces the reliability of the generated data and establishes a solid foundation for a standardized approach, enabling precise inter-laboratory comparisons and contributing to the overall integrity of our network's clinical results. Herein, we will provide a brief elaboration on the specific measures and procedures implemented to standardize the transfer of assays across our network.

Fig. 1. Trends in S-ELISA reference standard and controls.

The trends in the reference standard (21/360) and high and low controls (21/364 and 21/362) for S-ELISA in one of the CLN facilities between February 2023 and January 2024 are presented.

Fig. 2. Percentages of passed plates for different assays in various facilities.

The percentage of passed plates for each assay is shown in a few active testing facilities during the SARS-CoV-2 pandemic. Actual numbers of plates tested are shown in parentheses.

Fig. 3. Assay transfer.

The development and validation of assays are crucial steps that are performed in the reference facilities to ensure accuracy and reliability. Once the assays are validated, they are transferred to the designated receiving facilities, as illustrated below. The average timeline for the transfer of assays typically ranges between 3 to 8 months. However, it is important to note that this timeline may vary based on several factors, such as obtaining necessary shipping permits, variations in infrastructure or quality systems in facilities, particularly those located in low- and middle-income countries (LMICs), and other considerations.