Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2021 Jul 5;39(30):4013-4024.
doi: 10.1016/j.vaccine.2021.05.099. Epub 2021 Jun 1.

Evaluation of post-introduction COVID-19 vaccine effectiveness: Summary of interim guidance of the World Health Organization

Minal K Patel  1 , Isabel Bergeri  2 , Joseph S Bresee  3 , Benjamin J Cowling  4 , Natasha S Crowcroft  2 , Kamal Fahmy  5 , Siddhivinayak Hirve  2 , Gagandeep Kang  6 , Mark A Katz  7 , Claudio F Lanata  8 , Maïna L'Azou Jackson  9 , Sudhir Joshi  10 , Marc Lipsitch  11 , Jason M Mwenda  12 , Francisco Nogareda  13 , Walter A Orenstein  14 , Justin R Ortiz  15 , Richard Pebody  7 , Stephanie J Schrag  3 , Peter G Smith  16 , Padmini Srikantiah  17 , Lorenzo Subissi  2 , Marta Valenciano  18 , David W Vaughn  17 , Jennifer R Verani  3 , Annelies Wilder-Smith  2 , Daniel R Feikin  2
Affiliations

Evaluation of post-introduction COVID-19 vaccine effectiveness: Summary of interim guidance of the World Health Organization

Minal K Patel et al. Vaccine. .

Abstract

Phase 3 randomized-controlled trials have provided promising results of COVID-19 vaccine efficacy, ranging from 50 to 95% against symptomatic disease as the primary endpoints, resulting in emergency use authorization/listing for several vaccines. However, given the short duration of follow-up during the clinical trials, strict eligibility criteria, emerging variants of concern, and the changing epidemiology of the pandemic, many questions still remain unanswered regarding vaccine performance. Post-introduction vaccine effectiveness evaluations can help us to understand the vaccine's effect on reducing infection and disease when used in real-world conditions. They can also address important questions that were either not studied or were incompletely studied in the trials and that will inform evolving vaccine policy, including assessment of the duration of effectiveness; effectiveness in key subpopulations, such as the very old or immunocompromised; against severe disease and death due to COVID-19; against emerging SARS-CoV-2 variants of concern; and with different vaccination schedules, such as number of doses and varying dosing intervals. WHO convened an expert panel to develop interim best practice guidance for COVID-19 vaccine effectiveness evaluations. We present a summary of the interim guidance, including discussion of different study designs, priority outcomes to evaluate, potential biases, existing surveillance platforms that can be used, and recommendations for reporting results.

Keywords: COVID-19; Vaccination; Vaccine effectiveness.

PubMed Disclaimer

Conflict of interest statement

Declaration of Competing Interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: The following authors have disclosures to make. Gagandeep Kang is vice chair of CEPI, is on the board of directors of Ignite Life Science Foundation, and her institution receives funding in her capacity as independent director of the MSD Wellcome Trust Hilleman Laboratories Private Limited. Claudio F. Lanata’s institution has received research funding for COVID-19 vaccine studies from CureVac AG. Maïna L’Azou Jackson was an employee of Sanofi Pasteur until January 2020. Marc Lipsitch receives financial support from Bristol Myers Squibb and Sanofi Pasteur related to general COVID-19 work for presentations. He participates on the data safety monitoring board or advisory boards of Covaxx, Pfizer, Janssen, Astra-Zenca, One Day Sooner (all unpaid). He is a former unpaid board member of One Day Sooner. He also receives general support from the Morris Singer Foundation and the National Cancer Institute/National Institutes of Health USA. Walter A. Orenstein is a member of the Scientific Advisory Board for Moderna. Justin R. Ortiz receives honoraria and travel support for participation on scientific advisory board for Immunization for All Ages (Pfizer); honoraria and travel support for participation on scientific advisory board for Real World Evidence (Seqirus); his institution receives research funding for COVID-19 vaccine studies from NIH and Pfizer. Peter Smith is a member of the Data Safety Monitoring Board for Imperial College’s trial of SARS-CoV-2 vaccine, for Curevac’s trial of SARS-CoV-2 vaccine, and for Imperial College and Oxford University’s human challenge trials with SARS-CoV-2. Note that as we do not discuss any specific brand of vaccine, we do not feel any of these disclosures are a conflict of interest, but in the interest of transparency we have detailed relationships with pharmaceutical and other organizations.

References

    1. World Health Organization. “WHO Coronavirus Disease (COVID-19) Dashboard.” Retrieved June 3, 2021, from https://covid19.who.int/.
    1. Our World in Data. “Coronavirus (COVID-19) Vaccinations.” Retrieved March 10, 2021, from https://ourworldindata.org/covid-vaccinations.
    1. World Health Organization. “Evaluation of COVID-19 vaccine effectiveness: Interim Guidance, 17 March 2021.” Retrieved March 28, 2021, from https://www.who.int/publications/i/item/WHO-2019-nCoV-vaccine_effectiven....
    1. World Health Organization. “Clinical management of COVID-19: Interim Guidance.” Retrieved January 15, 2021, from https://www.who.int/publications/i/item/clinical-management-of-covid-19.
    1. World Health Organization. “WHO surveillance case definitions for ILI and SARI.” Retrieved March 10, 2021, from https://www.who.int/influenza/surveillance_monitoring/ili_sari_surveilla....

Publication types