Reversals of scientific conclusions are not unusual

I have started wearing a mask again when I go to the bridge center even though everyone has to prove that they are vaccinated before they are allowed to enter. The reason is the revised CDC guidelines that once again recommend indoor masking, especially in areas of high covid-19 incidence, because of the surge in cases due to the Delta variant.

There have been some criticisms of the CDC reversing its policy on masks. While I think that it can be faulted for less than clear messaging, I think the more fundamental problem is one over which they have no control and that is that people have a poor idea of how the scientific process works. People tend to think that scientific conclusions are fixed once and for all once they are arrived at and get unsettled when ‘science’ says one thing at one time and another thing later. But as I argue in my book The Great Paradox of Science, reversals of scientific consensus judgments happen all the time. It is just that it usually happens without the full glare of the media spotlight them so people are not aware of how common they are. In the case of covid-19, we are all getting to witness in real time that scientific conclusions are always provisional and that the scientific community can change its view when the situation changes and new evidence emerges. That is how it should be.

In the case of covid-19, the new danger is that even fully vaccinated people can get infected, in what are referred to as ‘breakthrough’ cases, so even vaccinated people like me should take precautions because there are still so many people who stupidly refuse to take the vaccine and can be the vectors of infections. The risks are small but not zero. Currently 161 million people in the US are vaccinated. The CDC estimates that there are 153,000 symptomatic breakthrough cases or less than 0.1% of the vaccinated population. According to the CDC, 1,141 breakthrough cases have resulted in death. This is tiny (0.00007%) but death is death and to be avoided if possible by taking simple precautions like wearing masks in indoor settings.

The existence of breakthrough cases doesn’t mean that vaccines aren’t doing their job, experts say. In fact, merely  coming down with a mild infection rather than a severe one is often evidence that the vaccine is doing its job in helping your immune system fight the virus. Since the existing vaccines were developed to combat the alpha variant of SARS-CoV-2, it makes sense that they’re not as effective in combating the delta variant, whose mutations have shown to some extent to evade the immune response from the vaccines. Yet all the COVID-19 vaccines are mostly able to stop the infection worsening.

“In a vaccinated person, what will happen is that we already have cells that very specifically recognize an infected cell, and can aggressively target that infection so that the virus can no longer replicate,” said Dr. Nicole Baumgarth, a professor of Immunology and Infectious Diseases at University of California–Davis. “Even if we cannot stop the infection from happening, [the vaccine] stops it very early in its tracks; the less virus replication you have, the less symptoms you will have, the less disease and it gets easier for the immune system to mop up the little bit of virus.”

What are the symptoms that indicate a possible breakthrough infection in a fully vaccinated person?

Generally, we saw similar symptoms of COVID-19 being reported overall in the app by people who had and hadn’t been vaccinated. However, fewer symptoms were reported over a shorter period of time by those who had already had a jab, suggesting that they were falling less seriously ill and getting better more quickly.

Here is the current ranking of COVID symptoms after 2 vaccinations:
1. Headache
2. Runny nose
3. Sneezing
4. Sore throat
5. Loss of smell

The previous ‘traditional’ symptoms as still outlined on the government website, such as anosmia (loss of smell), shortness of breath and fever rank way down the list, at 5, 29 and 12 respectively. A persistent cough now ranks at number 8 if you’ve had two vaccine doses, so is no longer the top indicator of having COVID.

Curiously, we noticed that people who had been vaccinated and then tested positive for COVID-19 were more likely to report sneezing as a symptom compared with those without a jab.

If you’ve been vaccinated and start sneezing a lot without an explanation, you should get a COVID test, especially if you are living or working around people who are at greater risk from the disease.

It is disappointing to have to go back to masks but it is hardly a huge burden. What is far more annoying are those who, in the face of all the evidence, still refuse to get vaccinated. The decision by Joe Biden to mandate that all federal workers must be vaccinated or be subject to distancing and regular testing will not only increase the numbers but also provide cover to other organizations that were thinking of taking similar measures.

Facing a daunting political test as the Delta variant cuts a swath through unvaccinated Americans, the president outlined a more aggressive approach by the federal government and expressed hope that it would offer a model for corporate employers.

The federal government is America’s biggest employer, including about 2.18 million civilian workers, while another 570,000 people work for the postal service, according to 2020 data. The workers are spread across the country, including many in states where vaccine scepticism runs high.

Paul Light, a public service professor at New York University, told the Associated Press before the announcement, “If the federal government were to say that everybody who works for the government directly or indirectly must be vaccinated, that’s a massive footprint.”

But of course, there will be pushback from the usual suspects.

But not for the first time, the pandemic response in the US is hampered by partisan politics and a growing divide between the vaccinated and unvaccinated. Biden’s intervention was likely to produce a renewed backlash from Republican politicians warning against government encroachment on individual freedom.

But the pandemic response continues to divide the country, with some Republicans already pushing back at the new guidance.

Ralph Norman, a congressman from South Carolina, said: “To require individuals to provide proof of vaccination would be a massive intrusion on the doctor-patient relationship and the privacy of the individual.”

Many Republican state leaders are blocking preventive measures, potentially making it harder to tame virus outbreaks in conservative communities. At least 18 Republican-led states have moved to prohibit vaccine passports or to ban public entities from requiring proof of vaccination. Some have prohibited schools from requiring any student or teacher to wear a mask or be vaccinated.

Let’s see how this goes.


  1. TGAP Dad says

    Under the COVID symptoms after two vaccinations, numbers 1 through 4 are also symptoms of “living in Michigan,” which I do. Allergies are a year-round phenomenon here, which makes COVID just an order of magnitude distinction (until it kills you).

  2. jrkrideau says

    “To require individuals to provide proof of vaccination would be a massive intrusion on the doctor-patient relationship and the privacy of the individual.”

    I thought all US states required proof MMR vaccination for admitting children to public schools.

    Ralph Norman seems as well informed as some of our politicians in Canada who cannot seem to master the concept of Federal vs Provincial juristictions (Hi Erin, hi Jagmeet).

  3. billseymour says

    I’m currently employed as a computer programmer by the U. S. Postal Service and subject to a union contract.

    It turns out that my shop steward is an anti-vaxxer; and he recently sent out an e-mail message complaining about the requirement for federal workers to be vaccinated.  He says that he’s a “libertarian” which, these days, seems to mean “Randian egoist”.  He also says that we’re all “entitled to our own opinions”, always a conversation stopper, and one that makes no sense unless there’s no such thing as expertise and everyone’s opinion is equally valid.  And he thinks that “personal freedom” is more important than “public health”, which I find disgusting.

    Disclaimer:  “If this were my employer’s opinion, I wouldn’t be allowed to post it.” — Norman Diamond

  4. Matt G says

    This should be much easier for people to understand than “scientists change their minds all the time.” The reversal is a function of a huge number of individuals deciding to not get vaccinated, not wear masks and not maintain social distance. It’s merely following the evidence as people’s behavior cause the evidence to change.

  5. garnetstar says

    The new policies are because it’s a new virus. It’s a surge of new virus because people didn’t mask and vaccinate. Is that difficult?

  6. mnb0 says

    “People tend to think that scientific conclusions are fixed once and for all once they are arrived at and get unsettled when ‘science’ says one thing at one time and another thing later.”
    This could be an interesting topic for research. My hypothesis: the more popular the abrahamistic religions the more people think like this. They belong to the Greek-Hebrew-Christian tradition that assumes we can get a grip on reality by sheer thinking. I’ve met many an apologist that claimed that empiricism was dead and buried.
    You don’t need to be a rocket scientist (I am far from one) to understand that new empirical data can lead to revision of conclusions. In the case of the corona crisis initially few empirical data were available, so it’s unsurprising that conclusions changed relatively quickly.

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