It was the best of interviews, it was the worst of interviews. At times I was born aloft on the wings of enlightenment, other times I feared I would drown in a sludge of foolishness. On the one hand was belief, on the other, incredulity. In short, I felt the torment of whiplash, but I lived to tell the tale.

Martin Kulldorff has been in the news a lot, lately. ACIP’s not going well. Dr. Kulldorff expressed an uncharacteristic lack of supreme confidence in himself, saying “We are rookies.” Dr. Kulldorff annoys me and I rarely if ever agree with him. However, sometimes I take a step back and assess whether my thinking is too rigid or biased. So I searched for writings or an interview with Dr. Kulldorff where he could express himself without restriction and I would just “listen.”

Comparing apples to apples

I came across an interview he did on a podcast called ”The Common Bridge,” (see: Dr. Martin Kulldorff – TheCommonBridge.com ) which is hosted by Richard Helppie. I hadn’t heard of Richard Helppie or “The Common Bridge.” Mr. Helppie appears to live in Michigan and his website suggests he tries to be non-partisan. The date of the interview is unclear, but took place after the Great Barrington Declaration and before the COVID vaccines were out.

I read the interview’s transcript and Mr. Helppie was respectful toward Dr. Kulldorff, while also asking a few questions that might have been a little challenging. He gave Dr. Kulldorff a forum for expressing his views in an unfettered setting. The episode was named, “The Great Barrington Declaration.” It was an opportunity for Dr. Kulldorff to explain in more detail his approach to handling the COVID epidemic.

I came away from the interview still irritated with Dr. Kulldorff. He made various assertions that weren’t supported with solid evidence and a couple of his suggestions made me laugh out loud.

That exercise completed, I browsed Mr. Helppie’s website to see who else he has interviewed. An episode with a Dr. James R. Baker, titled, “Vaccines, Public Trust, and What We Got Wrong About COVID,” caught my eye. (see: Dr. James R. Baker, Jr. MD – TheCommonBridge.com ) I wondered if this was an interview with one of America’s Frontline Doctors or someone like that.

I pulled up the Dr. Baker transcript and read it. It took place between the time when the COVID vaccines first came out and before children were eligible for them. Dr. Baker is great! He is articulate and enlightening, and I found him credible.

What explained the difference?

Reading the two transcripts back-to-back made me think about why I was so much more accepting of Dr. Baker than of Dr. Kulldorff. With the written interviews I could review them and compare how they frame decision-making. Below are several aspects of the differences in their approach to problem-solving.

What is the Nature and Depth of the Speaker’s Expertise?

James R. Baker, Jr, MD, is an immunologist. This link gives his education and work experience (James R. Baker, Jr. – Banaszak Holl Group). Briefly, he graduated from the Loyola Stritch College of Medicine and did his residency and fellowship at the Walter Reed Army Medical Center. He has been a professor in the Division of Allergy and Clinical Immunology at the University of Michigan. Among other activities he has been a Co-Chair of the American Academy of Allergy, Asthma and Immunology’s Vaccines and Biological Threats Committee, a board member of the Region V (Great Lakes) Regional Center of Excellence for Biodefense and Emerging Infectious Diseases and was on active duty with the U.S. Army for 14 years where he was involved in Biodefense.

Martin Kulldorff received his PhD in operations research from Cornell University with a concentration in applied probability and statistics. He has developed statistical methods for early identification of disease outbreaks and for geographical and hospital disease surveillance (SaTScan). His methods are also used by the Vaccine Safety Datalink to identify vaccine safety signals. He is a member of the U.S. Food and Drug Administration’s Drug Safety and Risk Management Advisory Committee, was formerly on the Vaccine Safety Subgroup and was recently appointed chair of the CDC’s Advisory Council on Immunization Practices.

Since both interviews covered actions that should be taken to mitigate the COVID pandemic, Dr. Baker’s expertise is more relevant. Dr. Kulldorff’s expertise is strongest in the timing, location, and frequency of cases. This is important, but doesn’t necessarily tell us what should be done about it.

Does the Speaker Rely on Appeals to Authority?

During his interview Dr. Kulldorff, stated:

Because ever since the beginning [of the pandemic], what the media was talking about – the scientific consensus – were things that we did not agree with. And we have all worked in this area for a long time. Dr. Sunetra Gupta is, in my view, the world’s pre-eminent infectious disease epidemiologist. So somehow other people were listened to, instead of what I thought was the most prominent people.

Various criteria could be used to determine who is the most “pre-eminent” infectious disease epidemiologist. Dr. Kulldorff provided no other details about why he thought Dr. Gupta is the most pre-eminent. I googled “world’s most pre-eminent infectious disease epidemiologist” and searched the archives of an epidemiology newsletter I receive (Epidemiology Monitor). I didn’t get any hits on Dr. Gupta. This doesn’t mean Dr. Gupta isn’t an expert in epidemiology (although her PhD is in biology). It likely indicates the problem of using vague terms when making an assertion, or in using criteria based on what you “think.” Dr. Gupta is a theoretical epidemiologist in the Department of Biology at Oxford University (UK) who uses mathematical models to uncover patterns of diversity in the evolution of pathogens. She has done work in influenza vaccine development. She has also published five novels!

A contemporary name that did pop up under “world’s most pre-eminent infectious disease epidemiologist” is David Heymann, Professor of Infectious Disease Epidemiology at the London School of Hygiene and Tropical Medicine. Dr. Heymann has experience in responding to outbreaks due to Ebola (1976), SARS (2003), swine flu (2009), MERS (2012), and COVID (2019), among others. He was also on the team that eliminated smallpox through vaccination. (I did not find any interviews or articles from Dr. Heymann where he advocated “focused protection” as a response to COVID-19 or any other pathogen.)

Dr. Baker did not use appeal to authority to support any of his statements. He did mention that he trained under Dr. Anthony Fauci. The context was that Dr. Baker felt that politics needed to be removed from decisions about managing the response to COVID. He referenced a statement Dr. Fauci had made, a.

I mean, Tony Fauci is one of my mentors, I trained under him 40 years ago, they made a statement the other day that he was particularly happy to see Republican senators supporting vaccination. You know, I mean, we can’t make this a Republican and Democratic thing.

Dr. Baker was willing to gently criticize one of his “authority figures.”

Dr. Baker also did not agree with some of the messages that came from the CDC, for example, he questioned the study that was done on 5000 people who attended an event in Provincetown, Massachusetts and which prompted a recommendation that vaccinated people should wear masks. Without getting into the weeds, he was skeptical of the results derived from PCR testing which: 1) doesn’t distinguish between live and dead virus; and 2) amplifies the genetic material 30 million times, making it hard to tell the significance of the finding.

Does the Speaker’s Expertise Expand Exponentially?

I think we all know the answer to this one. Dr. Kulldorff never rejects a label of expertise given to him. He’s a biostatistician, epidemiologist, infectious disease expert, vaccine safety expert, public health expert… you name it (although no one has called him an expert in self-awareness). I would be interested to hear what he has to say about statistical methods that identify the early signs of outbreaks. Other than that, I would need to hear from others with depth of knowledge and experience before accepting his positions on the other topics listed. I say this as someone who has worked for 30 years with physicians from various specialties. I’ve picked up a fair amount of clinical knowledge, but there is no way I should be diagnosing and treating patients.

Dr. Kulldorff:

Another thing is those people who are in their sixties, who are in the working age group, if they can work from home, yes, they should continue to work from home. But if they cannot, I think we have to help protect them so that they can take a sabbatical for three to six months while the transmission is high in society.

I did laugh at this statement. Sure, if you’re a grocery store worker, a truck driver, a nurse, a janitor, etc., just ask your employer for a sabbatical.

Dr. Kulldorff:

We also need to do less rotation of staff in nursing homes so that each doesn’t see too many patients.

Has Dr Kulldorff talked to any nursing home administrators about this? Because this does not sound feasible. (see: State Of The Sector: Nursing Home Labor Staffing Shortages Persist Despite Unprecedented Efforts To Attract More Staff )

The preceding examples show that it can be risky to claim expertise that you don’t have. As an aside, when asked, “To date, what have been the proudest achievements of your distinguished career?” Dr. Heyman replied, “I can’t claim any of those achievements myself because there were always teams involved.” (see: Interview: David Heymann CBE – European Medical Journal).

Dr. Baker’s discussion was very focused on vaccines and vaccine safety, COVID tests, and the circumstances under which masks work and who needs to wear a mask (answer = unvaccinated people). He really hammered on the benefits of getting vaccinated. “If you decide not to get vaccinated then wear a mask.” (a paraphrase) He didn’t say he was an epidemiologist or an expert in child development or mental health or business operations and he didn’t talk about those areas.

Does the Speaker Couch Their Arguments in Absolute Terms?

Dr. Kulldorff often states his positions definitively:

And herd immunity is not some strategy or something controversial because herd immunity is just scientific fact, scientific phenomena that’s proven, and that we will reach [it] sooner or later with this COVID-19, that’s unavoidable.

If true, it sounds like it’s going to be so far, far into the future that we can’t rely on it for near term decision making. Perhaps in a textbook example, with a closed population within a short period of time, herd immunity could be achieved if an infectious disease could penetrate it at a rapid rate. However, most epidemiologists are aware that people travel in and out of populations, children are born, people age, and immunity doesn’t always last. In dynamic populations like that there may be a high enough proportion of immunologically naive people that herd immunity is never achieved. The only disease to which the world has herd immunity is smallpox – achieved through vaccination. (Additionally, I pretty much ignore statements that include “it’s scientific fact.”)

…natural infection is always the best, most effective way to get immunity.

Statements from the previous paragraph apply here as well. What determines whether a strategy is “the best”? From a public health perspective vaccine-induced immunity is more predictable and easier to track (see: Vaccination and natural immunity: Advantages and risks as a matter of public health policy – PMC ) How much “better” is natural immunity than vaccination? Does Dr. Kulldorff feel it is worth it to expose himself to RSV, monkeypox, or tuberculosis so he can have the very best immunity that pathogens can provide?

Dr. Baker is consistent in saying, “based on the data we have now” or “the most recent data that has come out shows…” He states the context that he knows. For example, Richard Helppie asked him about gain of function research. Dr. Baker first noted his relevant experience in this area (he was in the military for 14 years where he was involved in biodefense). He explained what it is, i.e., “A purposeful attempt to engineer something to harm people, and do it in a more efficient way.” He said that one of the ways the U.S. tries to keep tabs on what other countries are doing is to fund some of their research. From what he had seen, the lab at Wuhan was not doing gain of function research, but rather research to better understand how viruses evolve in nature to become better at causing disease in humans. He followed that with, “Now, there may be things there that I’m not aware of.” He also said that nature is much better than humans at gain of function research: “…we were talking about worrying about Gain-of-function engineering, the most effective engineering in the world, is allowing the virus to replicate in hundreds of millions of people.”

Does the Speaker Use Anecdotes to Support Their Statements?

Regular readers of Science-Based Medicine know that anecdotes are not evidence. Dr. Kulldorff states,

I am a native of Sweden so I talked to my brother and sister there, and other people in Sweden, and life is fairly normal.

Presumably this was if you were under the age of 70. What part of Sweden do these people live in? Dr. Kulldorff grew up in Umeå, “close to the Arctic circle.” (see: Dr. Martin Kulldorff Joins Brownstone Institute as Senior Scientific Director ⋆ Brownstone Institute Brownstone Institute). Do his brother and sister live in an outlying town where life might be relatively normal? And surely an epidemiologist and statistician like Dr. Kulldorff would understand the importance of using proper techniques to obtain a representative sample of Swedish citizens. He didn’t select like-minded individuals to talk to, did he?

I didn’t find a similar narrative from Dr. Baker. The closest he came to one is,

…if I’m your doctor, or I’m your, your husband, or your brother, or whatever, I would tell you absolutely get vaccinated, because it’s the right thing to do.

Does the Speaker Make Statements That Make Your Brows Furrow?

My wrinkles will multiply if I read Dr. Kulldorff’s writings too frequently. We have already reviewed “Herd immunity is a scientific fact and unavoidable.” In another case, Dr. Kulldorff was arguing that children rarely transmit COVID to adults. He mentioned “…a very interesting study in Iceland, where they looked at genetics of the virus to see who is actually infecting who – and they found that while parents will often infect children, children will not infect parents very often.” (What about infecting other children, though?)

“Gerrymandering” approach

The context for this statement was Dr. Kulldorff’s assertion that schools should be open so that students could attend in person, and he wanted to demonstrate that teachers were not at risk. This was part of what I would call a “gerrymandering” approach where one starts with the desired conclusion, “Open schools for in person attendance” and then create the constellation of results that support it, i.e., “children don’t transmit COVID to teachers” and “COVID doesn’t make children sick.” The reference isn’t given but this study from Iceland (see: SARS-CoV-2 Infections in Icelandic Children: Close Follow-up of All Confirmed Cases in a Nationwide Study – PMC ) states that

Iceland had the good fortune of having developed very stringent control of infected patients through isolation and quarantine of exposed individuals as well as mass testing of the population—a factor likely to reduce community spread.

This might explain some of the results and certainly doesn’t translate well to the United States.

Dr. Baker’s discussion on the subject of opening schools:

You know, the best way to get everybody back to school and protect every teacher is have every teacher and every adult in those schools vaccinated, just like healthcare workers.

Dr. Kulldorff:

[COVID-19 is] much less dangerous than the annual flu for children.

Since Dr. Kulldorff was interviewed either at the end of 2020 or early in 2021, this time period is most relevant for evaluating this statement. Finding precise data on a comparison is rather difficult. According to CDC Wonder (https://wonder.cdc.gov, accessed 28Sep2025), annual U.S. death rates for the flu (2018-2023) and COVID (2020-2023) for four age groups are given below:

On this basis we would not conclude that COVID-19 is much less dangerous than the annual flu for children. And of course, this does not account for hospitalizations or long-term health consequences due to COVID.

Where did that come from?

Dr. Kulldorff also mentioned:

…a very interesting study from Toronto, Canada. Before the lockdown mortality was the same in all socio-economic groups, but then after lockdowns went in place, the highest socio-economic groups they flattened with the mortality, while the lower socio-economic groups continued to rise until it then eventually came down again because [of] increasing immunity.

Really? The same mortality rate across all socioeconomic groups? That would be unusual. We are not provided with a citation of the study to which Kulldorff refers. This report from Statistics Canada (see: Extent and socioeconomic correlates of small area variations in life expectancy in Canada and the United States ) suggests that life expectancy varied little among socioeconomic groups in Toronto between 2006-2016. Their methods appear to involve crude rates based on annual average death counts per census tract.

On the other hand, the age-standardized mortality rates in this report from Toronto Public Health (see: HSI: All-Cause Mortality and Life Expectancy ) show a clear increasing trend in mortality rate as income declines, over the period 2001-2010. I did not find a source that provided trends in age-standardized mortality rates by socioeconomic indicators in Toronto after the onset of the COVID pandemic (although I didn’t do an extensive search).

Regardless, Dr. Kulldorff’s point related to the above was this:

So we were actually, again in quotation marks, ‘successfully’ protecting the more privileged professional class, shifting the burden on the working class. So that was a ‘success’, and again, in quotation marks, because I think it’s a terrible outcome. So in the same way we can do what the Great Barrington Declaration is arguing for, we should do that separation – instead of by privilege versus working class – we should do it by age, because that’s where the risks are.

His argument for separating and protecting older people has a murky link to the socioeconomic disparities in COVID mortality he’s concerned about. Is he saying people who cannot work from home are all elderly? Or is he saying the “privileged” people who work from home should get off their asses and get back to the office? It seems that if we focus on “protecting the elderly,” the people under age 70 who cannot work from home will still be going to work outside the home and suffering “the burden on the working class.” And if the “privileged” people go back to the office, the people from the “working” classes will potentially have even more exposure to infected individuals.sw

I did not find any statements by Dr. Baker that made me wonder, “Where did that come from?”

Cherry-picking

I note another pattern that is specific to Dr. Kulldorff and not Dr. Baker: apparent cherry-picking of studies whose results fit his wishes. “There was an interesting study ….” I should also note that Dr. Kulldorff’s interview occurred prior to the availability of COVID vaccines, while Dr. Baker’s was afterwards. So it’s possible some of Dr. Kulldorff’s recommendations might have included getting vaccinated. On the other hand, his extolling of “natural immunity” does not assure us of this, nor does getting fired from Harvard for refusing to get vaccinated.

Dr. Baker would mention data that he had reviewed without giving details on the study or a citation. My feeling, and it is a feeling, was to believe him since he was so solid in the rest of his discussion. But it could be something to keep in mind.

Conclusions

So ends the tale of two interviews, one science-based and the other wish-based. Science-based thinking uses observations and the knowledge built by scientific methods to draw inferences. During Dr. Baker’s interview, he used the word “data” 14 times, often in reference to study data to which he had access. Dr. Kulldorff said “data” two times. (Mr. Helppie seems to have been a “control” because he used the word “data” five times during Dr. Baker’s interview and six times during Dr. Kulldorff’s interview.) The wish-based thinker starts with a favored outcome and pastes together a collage of arguments for it. “I wish schools could be open,” therefore, “children don’t get sick from COVID” and “children don’t transmit COVID to adults.”

A wish-based thinker never rejects a study that grants their wish. It’s like finding a pearl in an oyster or that perfect sweater on sale. The science-based thinker understands that studies do not grant wishes, they produce evidence, and the task before them is to evaluate the quality of that evidence. Is it coherent with the solid knowledge we already have? If not, it needs to be damn good evidence that is reproduced by other careful scientists. That’s something for the future and until then, the science-based thinker doesn’t act on it.

The best spin that could be placed on Dr. Kulldorff’s wish-based thinking is that it springs from an aspirational mindset. It would be nice if we didn’t have to close schools, or wear masks during a pandemic. It would be great if those of us who enjoy it could attend crowded social gatherings when a novel virus is spreading through a population. Physicians like Dr. Baker don’t roll the dice with people’s lives. The science-based knowledge and data they use produces the reliable predictions needed for choosing the best response. We can wish that another pandemic won’t come along. But science predicts otherwise, and my money is on science.

Lynn Shaffer, PhD, is an epidemiologist and statistical analyst with the Mount Carmel Research Institute where she supports investigator-initiated clinical research. Dr. Shaffer has no competing interests to disclose, financial or otherwise. Her views with respect to this work are her own and not associated with or endorsed by Mount Carmel Research Institute or Mount Carmel Health System.

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