Antibody response to COVID-19 vaccines
Developing, licensing and deploying vaccines against an emerging pathogen declared a global public health emergency presents many challenges, including accelerated timelines to assess the safety and efficacy of candidate vaccines. Regulatory processes must be in place for rapid evaluation of submissions and, after careful benefit-risk assessment, use of vaccines for which a full regulatory package may not yet be available, such as during the COVID pandemic -19 declared in 2020.
A wide range of candidate vaccines against COVID-19 are being developed through technologies and platforms that include viral vectors, protein subunits, nucleic acids, live attenuated strains and inactivated virus preparations.1 , 2
One of the important elements of regulatory evaluation is the measurement of the vaccine-induced immune response, for which guidance is available in the WHO guidelines for the clinical evaluation of vaccines.
3 The evaluation of the immunogenicity of a vaccine aims to identify a possible correlate of protection. Although it is still unclear what such a correlate might be for SARS-CoV-2, neutralizing or binding antibodies are good candidates. However, identifying a correlate of protection requires comparison of immunological data from different clinical trials, but is often confounded by differences in assays, target antigens, numerical readings, and parameters.
This personal perspective aims to raise awareness of the need to standardize quantitative tests for the evaluation of clinical trials of vaccines for use in public health emergencies. The first step towards standardization is the availability of a WHO international standard that will serve as a reference point for several tests of defined specificity.4, 5 In May 2020, a research reagent for the anti-SARS- CoV-2 was made available as an interim solution while a collaborative study with International Standard applicants was conducted.
A WHO international standard for neutralizing activity of anti-SARS-CoV-2 immunoglobulin has been available since December 2020, but its usefulness in enabling comparability between vaccines, between laboratories and over time cannot be disputed. achieved only if the international standard is widely used. To advance standardization and comparability, it is important that the use of WHO International Standard Units becomes the norm in the reporting of serological tests for the quantification of antibody response.
WHO standards for evaluating the quality, safety and efficacy of vaccines
Developing, licensing and deploying vaccines against an emerging pathogen declared a global public health emergency presents many challenges, including accelerated timelines to assess the safety and efficacy of candidate vaccines.
Regulatory processes must be in place for rapid evaluation of submissions and, after careful benefit-risk assessment, use of vaccines for which a full regulatory package may not yet be available, such as during the COVID pandemic -19 declared in 2020.
A wide range of candidate vaccines against COVID-19 are being developed through technologies and platforms that include viral vectors, protein subunits, nucleic acids, live attenuated strains and inactivated virus preparations.1 , 2
One of the important elements of regulatory evaluation is the measurement of the vaccine-induced immune response, for which guidance is available in the WHO guidelines for the clinical evaluation of vaccines.
3 The evaluation of the immunogenicity of a vaccine aims to identify a possible correlate of protection. Although it is still unclear what such a correlate might be for SARS-CoV-2, neutralizing or binding antibodies are good candidates. However, identifying a correlate of protection requires comparison of immunological data from different clinical trials, but is often confounded by differences in assays, target antigens, numerical readings, and parameters.
This personal perspective aims to raise awareness of the need to standardize quantitative tests for the evaluation of clinical trials of vaccines for use in public health emergencies. The first step towards standardization is the availability of a WHO international standard that will serve as a reference point for several tests of defined specificity.4, 5 In May 2020, a research reagent for the anti-SARS- CoV-2 was made available as an interim solution while a collaborative study with International Standard applicants was conducted. A WHO international standard for neutralizing activity of anti-SARS-CoV-2 immunoglobulin has been available since December 2020, but its usefulness in enabling comparability between vaccines, between laboratories and over time cannot be disputed. achieved only if the international standard is widely used. To advance standardization and comparability, it is important that the use of WHO International Standard Units becomes the norm in the reporting of serological tests for the quantification of antibody response.
WHO has a unique role in supporting regulatory authorities in its 194 Member States. One of the main functions of WHO is to establish norms and standards, and to promote and monitor their implementation. The WHO Expert Committee on Biological Standardization has been actively involved in setting WHO standards for biological products for over 70 years.
WHO standards, whether written or measured (i.e. physical), are based on scientific evidence and serve as the basis for establishing and updating national regulatory requirements. Their development is supported by WHO collaborating centres, national regulatory authorities in many countries, pharmacopoeias, manufacturers' associations and universities.
The role of international recommendations or guidelines for biologicals is to ensure the availability of vaccines of assured quality, safety and efficacy for use in international immunization programmes. In addition, these documents serve as a reference for the overall acceptability of products and as the basis for defining national regulatory requirements for authorization and post-authorisation evaluation.
The development of measurement standards involves elaborate collaborative studies in many laboratories around the world. As examples of measurement standards for COVID-19, the WHO's first international standard for anti-SARS-CoV-2 immunoglobulin with an assigned unit of 250 international units (IU) per ampoule (activity of neutralizing antibodies) and the first WHO international reference group for anti-SARS-CoV-2
immunoglobulin were established by the WHO Expert Committee on Biological Standardization on December 10, 2020. 7, 8 By l through the WHO Collaborating Center, the National Institute for Biological Standards and Control, these standards were made available on December 18, 2020. 2020, under the code 20/136.
WHO standards, whether written or measured (i.e. physical), are based on scientific evidence and serve as the basis for establishing and updating national regulatory requirements.
Their development is supported by WHO collaborating centres, national regulatory authorities in many countries, pharmacopoeias, manufacturers' associations and universities.
The role of international recommendations or guidelines for biologicals is to ensure the availability of vaccines of assured quality, safety and efficacy for use in international immunization programmes. In addition, these documents serve as a reference for the overall acceptability of products and as the basis for defining national regulatory requirements for authorization and post-authorisation evaluation.
The development of measurement standards involves elaborate collaborative studies in many laboratories around the world. As examples of measurement standards for COVID-19, the WHO's first international standard for anti-SARS-CoV-2 immunoglobulin with an assigned unit of 250 international units (IU) per ampoule (activity of neutralizing antibodies) and the first WHO international reference group for anti-SARS-CoV-2