August 8, 2024 - Vaccines are sometimes tested against other vaccines or adjuvants instead of saline placebos to protect participants’ health when an effective vaccine is already available.

Against this backdrop, the WHO Department of Ethics and Social Determinants convened an expert consultation to provide recommendations on the use of placebo controls in vaccine trials in cases where an efficacious vaccine already exists. The focus was on large-scale clinical trials that test vaccines in Phases III and IV of development (i.e. where preliminary testing of safety and immunogenicity, and sometimes efficacy, has been completed in Phase I and II trials).

While placebo-controlled trials are often considered the gold standard for evaluating medical interventions, the use of inert placebos (e.g., the injection of saline solution) is not always required for vaccine trials and in fact is sometimes unethical.

January 18, 2025 - Last Monday’s newsletter about randomized controlled trials in vaccine development generated fascinating discussion and important questions from our readers. Many of you reached out with specific concerns that deserve a thorough response. Let’s address the main points of feedback: ... “Vaccines aren’t always compared to saline placebos — they’re sometimes compared to other vaccines.

Many childhood vaccines were tested originally in randomized clinical trials that included placebo or comparison groups. If the vaccine is for a disease that currently has no vaccine, the placebo may be saline or another substance known to be safe.

April 29, 2026 - Many people interpret this to mean a saline injection or sugar solution — and sometimes that is exactly what is used. However, in clinical research studies of vaccines, a control group can also receive another vaccine, an earlier version of a vaccine, or some comparator that allows researchers ...

July 6, 2020 - Against what does a vaccine need to be tested in the context of a clinical trial? The answer that pops immediately to mind is “a placebo.” In the medical sciences, things get compared to placebos to see if they have inherent potency or if it’s all about the theatre and natural circumstances surrounding them.

July 1, 2023 - When researchers at pharmaceutical ... immunologically inactive and harmless. The FDA would not allow any vaccine trials to proceed unless they deemed placebos to be true placebos....

May 6, 2025 - These often were tested in clinical trials in which people were randomly assigned to either receive the new vaccine or an older version, an example of what’s called an active control group.

January 17, 2025 - Many of you reached out with specific concerns that deserve a thorough response. Let's address the main points of feedback: ... "Vaccines aren't always compared to saline placebos – they're sometimes compared to other vaccines.

Many of you reached out with specific concerns that deserve a thorough response. Let's address the main points of feedback: Your Comments: "Vaccines aren't always compared to saline placebos – they're sometimes compared to other vaccines.

March 14, 2025 - A true placebo is an inactive ... but not in vaccine studies. Instead of saline, many vaccine trials use adjuvants like aluminum or even other vaccines as the placebo. Here are some examples of clinical trials and the "placebos" that were used:...

May 16, 2025 - Health Secretary Robert F. Kennedy ... evaluating vaccines, the plan did not seem so radical. New vaccines are often tested against a placebo in clinical trials....

July 23, 2025 - “Those new vaccines are always tested against a placebo control,” says Ellenberg, who monitored the safety of COVID-19 vaccines developed through Operation Warp Speed, a program started under the first Trump administration.

May 2, 2025 - Sometimes, during vaccine trials, participants in a comparison group are not given a placebo but another type of vaccine so that they can still receive some benefit from the study, Moss said.

June 21, 2014 - When the efficacy and safety of a novel vaccine is being assessed for the first time, societies, ethics committees, and parents accept this course of action on the grounds that although the vaccinated infant cannot derive any benefit from participating in the trial, other infants might do so in the future. However, the situation becomes more complex when investigators wish to test a new vaccine against a placebo when a safe and effective vaccine already exists.

While vaccine supplies are limited, available vaccines are still investigational, or public health recommendations to use those vaccines have not been made, we believe it is ethically appropriate to continue blinded follow-up of placebo recipients in existing trials and to randomly assign new participants to vaccine or placebo. Moreover, under these conditions, we believe that trial sponsors are not ethically obligated to unblind treatment assignments for participants who desire to obtain a different investigational vaccine. People who enroll in clinical trials for altruistic reasons would probably understand the value of gathering data that will further elucidate the safety and efficacy of these vaccines and their appropriate use.

February 28, 2022 - The expert panel concluded that placebo use in vaccine trials is clearly acceptable when no efficacious and safe vaccine exists and the vaccine under consideration is intended to benefit the population in which the vaccine is to be tested [14]. ...

May 22, 2025 - For years, regulators have evaluated new vaccines case by case — sometimes using placebos, sometimes comparing them with existing vaccines — based on what’s ethical and appropriate.