The forces seeking to undermine both the coronavirus vaccines and the Centers for Disease Control and Prevention’s handling of them have landed on a new gotcha moment.

It’s just not nearly the gotcha they seem to think.

Rep. Thomas Massie (R-Ky.) has been one of Congress’s biggest critics of the Centers for Disease Control and Prevention and the vaccination push. An intern recently resigned from his office over the congressman comparing vaccine “passports” to the Holocaust. (Massie later deleted the tweet.)

On Wednesday, Massie elevated something others had noticed in the days prior: that the CDC had updated a definition of “vaccination” on one of its webpages. As of late August, the page described vaccination as “The act of introducing a vaccine into the body to produce immunity to a specific disease” (emphasis ours). The definition has since been changed from producing “immunity” to producing “protection.”

“Check out @CDCgov’s evolving definition of ‘vaccination,’ ” Massie said. He then dropped another comparison — to George Orwell’s 1984: “They’ve been busy at the Ministry of Truth.”

The tweet has gone somewhat viral, with more than 9,000 retweets and more than 19,000 likes. Other social media posts noting the change have also been shared widely among the vaccine-skeptic community.

The idea is that the CDC is watering down the definition of vaccination in response to the coronavirus vaccines proving less effective against infection from the delta variant than previously. (The vaccines, however, remain very good at preventing serious cases and hospitalizations.).

“After the Covid-19 vaccines were introduced, and it was discovered they do not necessarily ‘prevent disease’ or ‘provide immunity,' ” says the website of longtime vaccine skeptic and former CBS News journalist Sharyl Attkisson, “CDC altered the definition of vaccines again to say that they merely ‘produce protection.’ ”

Massie responded to a critic by stating that “the goal posts have moved.” Some have even suggested that the definition needed to be changed to still consider the coronavirus vaccines to be vaccines at all.

It’s interesting that the CDC changed the Web page. But as for the conclusions being drawn about its significance? Those leave a lot to be desired, and they rest upon continual misrepresentations and misunderstandings of what vaccination and “immunity” are supposed to mean.

From the start of the vaccination campaigns, critics have searched long and hard for evidence that the vaccines don’t work as well as they were supposed to. This has sometimes involved suggesting that anything less than 100 percent efficacy means they don’t work.

In truth, though, medical experts have long said that no vaccine, including the coronavirus vaccines, is 100 percent effective. If “immunity” connotes complete protection, then no vaccine actually provides it.

Part of the reason people seem to believe immunity means 100 percent protection stems from how it’s understood in other contexts. Legally speaking, immunity from things like prosecution means you can’t be prosecuted, full stop. But in a medical contexts, it’s often used as a synonym for a specific type of protection — i.e. the same word the CDC now uses.

The Merriam-Webster Medical Dictionary defines immunity as “a condition of being able to resist a particular disease.” Taber’s Medical Dictionary defines it as, “Protection from diseases, [especially] from infectious diseases.” Harvard’s medical dictionary defines it as, “The body’s ability to resist infection and disease.” The Oxford Concise Medical Dictionary echoes all of them, saying immunity is “the body’s ability to resist infection.

(These definitions, it bears noting, have not been changed recently.)

The data clearly shows the coronavirus vaccines meet these definitions of providing immunity, as do other vaccines with less than 100 percent efficacy. Those include the flu vaccines, whose efficacy is generally around 40 percent. The flu vaccines are still vaccines and still provide immunity — just not complete immunity.

And to the extent this is some supposed grand conspiracy to move the goal posts on the coronavirus vaccines, it would also be a very incomplete one. Throughout its website, the CDC still refers to the coronavirus vaccines providing immunity:

The irony of all of this is that the theories about what the change really means actually reinforce the idea that it’s probably better to use “protection” than “immunity” — given that people don’t seem to understand what “immunity” actually means.

Others, though, seem to be deliberately obfuscating. On Wednesday, the same day Attkisson’s website suggested that the change was made because perhaps the vaccines don’t “provide immunity,” it updated another post acknowledging that immunity is indeed a relative term.

Of course, it did so in the service of making another argument Massie and others have focused on: that the immunity from infection provides more protection than, in its own words, “vaccine-induced immunity.”