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
Review
. 2023 May 22;41(22):3399-3402.
doi: 10.1016/j.vaccine.2023.04.033. Epub 2023 Apr 28.

Considerations for unblinding individual study participants during vaccine trials

Neal Halsey  1 , Stephen Evans  2 , Mathuram Santosham  3 , Adam Hacker  4 , Kathryn M Edwards  5 , Rebecca E Chandler  4 , Matthew Z Dudley  3 , Cornelia L Dekker  6 ; members of the SPEAC meta-DSMB; Seif Al-Abri  7 , Narendra Arora  8 , Jim Buttery  9 , Alex Dodoo  10 , Juhani Eskola  11 , Ulrich Heininger  12 , Youngmee Jee  13 , Najwa Khuri  14 , Stephen Obaro  15 , Walt Orenstein  16 , Punnee Pitisuttithum  17 , Marco Safadi  18 , Cynthia G Whitney  16 , Steve Black  19
Affiliations
Free article
Review

Considerations for unblinding individual study participants during vaccine trials

Neal Halsey et al. Vaccine. .
Free article

Abstract

Premature unblinding of individual participants is rarely reported in publications, but such unblinding can disrupt vaccine trials by causing worry and drop-out of other participants or "pseudo unblinding," in which participants or investigators over-interpret certain symptoms as being related to receiving an investigational product. This review summarizes appropriate reasons for unblinding in vaccine trials. Regulatory guidance could be improved by distinguishing guidance for vaccine trials from drug trials, with the recognition that unblinding individual participants in vaccine studies is rarely needed for management of adverse events following immunization.

Keywords: Adverse events; Regulatory guidance; Unblinding; Vaccine; Vaccine safety; Vaccine trials.

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: All authors received support from the Coalition for Epidemic Preparedness Innovations(CEPI) either directly or through a grant administered by the Task Force for Child Survival. NH reports ongoing support from Hillevax and Takeda, and past support from Pfizer, Valneva, and Inovio for service on safety reviews or DSMBs, and support from ILiAD Biotechnologies for an advisory board. CD reports a relationship with Dynavax Technologies Corporation that includes equity or stocks and service on a Scientific Advisory Board for Medicago. MD reports current research support from Merck and previous research support from Walgreens. CW reports suppoort from Moderna Inc that includes consulting or advisory. UH reports support from Pfizer Inc, Sanofi Aventis France, InfectoPharm Medicines and Advice GmbH that includes: speaking and lecture fees, from Takeda Switzerland and HilleVax that includes consulting or advisory. KE reports support from Pfizer, Moderna, GSK, Seqirus, Merck; Roche, Sanofi for sevice on advisory committees or DSMBs and consulting fees from Bionet and X-4 Pharma.WO serves as an uncompensated member of the Moderna Scientific Advisory Board. CW reports support from Moderna. MS reports consulting, advisory, or speaking and lecture fees with Pfizer, GlaxoSmithKline, Sanofi, Merck & Co Inc, AstraZeneca Pharmaceuticals LP, Janssen Pharmaceuticals Inc and board membership with Janssen. AH, RC, JB, SE, JE, NKA,SO,YJ, NB and PP report no conflicts.

LinkOut - more resources