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Fauci’s emails don’t support viral claims on masks, hydroxychloroquine and virus engineering

Fauci’s emails prove he knew that masks don’t work against the spread of COVID-19, that hydroxychloroquine is effective against COVID-19, and that the virus is likely engineered, and he lied about these things to the public
Inaccurate: Contrary to these claims, Fauci’s emails don’t prove that he knew masks don’t work, that hydroxychloroquine is effective against COVID-19, or that the virus is likely engineered. Scientific evidence shows that masks do reduce the spread of viral respiratory diseases like COVID-19 and that hydroxychloroquine isn’t effective as a COVID-19 treatment. Fauci’s emails don’t contain evidence that the virus is manmade.
Studies showed that masks reduce the spread of viral respiratory infections like COVID-19. Clinical trials found that hydroxychloroquine didn’t offer any meaningful benefit to COVID-19 patients. There is evidence showing that most people who had COVID-19 develop some level of immunity. But individual variability in immunity and virus variants mean that vaccination can still benefit a person who already had the disease. Scientific studies of the virus’ genome to date haven’t shown evidence that the virus was engineered in a laboratory. There is a lack of evidence that allows us to accept or reject the hypothesis of a laboratory accident with a high degree of certainty. At the moment, both zoonosis and laboratory escape remain plausible scenarios.

FULL CLAIM: Fauci’s emails prove “he knew all along that masks didn’t really work” and “the virus was likely engineered”; “Fauci Was Informed of Hydroxychloroquine Success in Early 2020 But Lied to Public”; Fauci knew of “substantial immunity” in survivors, meaning that survivors don’t need to be vaccinated


On 1 June 2021, Washington Post and Buzzfeed News published reports on several thousands of emails sent by Anthony Fauci, the director of the U.S. National Institute of Allergy and Infectious Diseases. The emails, sent during the first half of 2020, were provided in response to a Freedom of Information request filed by the Post and Buzzfeed. The emails documented Fauci’s exchanges with people across multiple sectors, including people seeking Fauci’s advice. Others showed his discussions with colleagues in the scientific community.

However, some interpreted the emails as evidence that masks don’t work against the spread of COVID-19, that hydroxychloroquine is an effective COVID-19 treatment, that the virus SARS-CoV-2 was likely engineered in a laboratory, and that COVID-19 survivors don’t need to be vaccinated (see examples here, here, here, and here). These claims aren’t new—they have circulated constantly throughout the pandemic, despite the fact that the claims aren’t supported by scientific evidence, and in some cases contradicted by evidence, as previous Health Feedback reviews showed. Altogether, these claims received more than hundreds of thousands of interactions on social media platforms like Facebook.

Overall, the claims surrounding Fauci’s emails build a narrative that attempts to discredit a prominent public health official, and in turn cast doubt over the necessity of public health measures taken to combat the pandemic.

This review will cover the evidence in relation to each of these claims, detail what Fauci’s emails said with regards to each claim, and demonstrate that they don’t provide evidence for any of these claims.

Scientific evidence demonstrates that mask-wearing reduces the spread of COVID-19

The evidence:
The U.S. Centers for Disease Control and Prevention recommends community mask use as a way to reduce the spread of the virus. Face masks are intended primarily to reduce the spread of liquid droplets and particles generated by an infected person (source control). The main mode of COVID-19 transmission is thought to be contact with infectious respiratory fluids. By reducing the amount of infectious liquid droplets and particles that are dispersed into the air, the virus’ spread from person to person is reduced.

Several published studies demonstrated that mask-wearing can reduce the spread of respiratory infectious diseases like COVID-19.

An April 2020 study published in Nature Medicine examined more than 100 people that shed various respiratory viruses, including seasonal coronaviruses and influenza, as well as the efficacy of face masks in reducing dissemination of infectious droplets[1]. The authors concluded that “Our results indicate that surgical face masks could prevent transmission of human coronaviruses and influenza viruses from symptomatic individuals.”

An April 2020 review published in the International Journal of Nursing Studies by MacIntyre and Chughtai analyzed 19 randomized controlled trials, evaluating the efficacy of face masks and respirators against the spread of various respiratory viruses, among which eight were conducted in a community setting[2]. The review concluded that, “In the community, masks appear to be effective with and without hand hygiene, and both together are more protective.”

A May 2020 study published in BMJ Global Health examined 124 families in Beijing, China, each of which had one member with a confirmed COVID-19 infection (primary case). The authors examined whether various interventions—specifically the use of disinfectants, physical distancing, and face masks—in a household reduced the spread of the virus to other family members[3]. They found that all three interventions reduced transmission of COVID-19 to others. Specifically, “Face mask use by the primary case and family contacts before the primary case developed symptoms was 79% effective in reducing transmission.”

A systematic review and meta-analysis by Chu et al., published in June 2020 by The Lancet, examined the efficacy of three interventions—physical distancing, face masks, and eye protection—in reducing the transmission of coronavirus infections (SARS, MERS, and COVID-19)[4]. The authors evaluated 39 studies testing the efficacy of various face masks in reducing disease transmission and found that face masks reduced the risk of coronavirus infection compared to no mask-wearing.

An article published in the Proceedings of the National Academy of Sciences of the United States of America in January 2021 reviewed the evidence supporting the use of face masks, particularly as source control. Evaluating a diverse array of studies that examined epidemiological evidence, transmission characteristics of respiratory viruses, and filtration capacities of face masks[5], the authors concluded that:

The available evidence suggests that near-universal adoption of nonmedical masks when out in public, in combination with complementary public health measures, could successfully reduce [the effective reproduction number] to below 1, thereby reducing community spread if such measures are sustained.

What Fauci’s emails said:
The claim that Fauci knew “masks don’t work” commonly referred to his response to Sylvia Burwell, a former U.S. Secretary of Health and Human Services, sent on 5 February 2020. Examples of this claim can be seen in this video by Brittany Hughes, managing editor of MRCTV, and this TikTok video uploaded on Facebook by political commentator Brandon Tatum. In total, both received more than hundreds of thousands of views on Facebook.

In his email to Burwell, he wrote that:

Masks are really for infected people to prevent them from spreading infection to people who are not infected rather than protecting uninfected people from acquiring infection. The typical mask you buy in the drug store is not really effective in keeping out virus, which is small enough to pass through the material. It might, however, provide some slight benefit in [keeping] out gross droplets if someone coughs or sneezes on you.

It is important to note that Fauci’s statements above are consistent with mask-wearing guidance at that point in time, when masks weren’t recommended for the general public. This was because health authorities were concerned about a potential shortage of masks, which are needed to protect healthcare workers at high risk of contracting the disease.

But in early April 2020, the U.S. Centers for Disease Control and Prevention reversed its stance on community mask use, after scientists discovered that seemingly healthy people could spread the virus[6-8].

In keeping with the change in guidance spurred by the emergence of new scientific evidence, Fauci has since encouraged mask-wearing numerous times in the media (see here, here, and here), as Reuters pointed out in their fact-check.

Fauci’s remarks on the virus size at that time were also interpreted by some as another reason that masks don’t work. This argument was advanced by some before, but as explained in this Health Feedback review, the argument turned out to be a specious one.

Alex Huffman, an aerosol scientist at the University of Denver, told FactCheck.org that “Early on in the pandemic, prevention messaging was coming primarily from infectious disease experts who have little to no training in aerosol science”.

Huffman explained that viruses themselves can indeed be too small for a paper or cloth mask to filter. However, “viruses don’t fly out of your mouth by themselves,” he said. “They are encased in droplets”.

In short, it is the size of the droplets that determine the efficacy of the face mask, not the size of the virus.

He also noted how the later change in perspective on mask effectiveness came about due to contributions from experts in aerosol science and reflected the role of collaboration in scientific progress. “To Dr. Fauci’s great credit,” Huffman said, “he changed his perspective, learned a little about aerosol physics, and started listening to a broader audience of experts, including aerosol scientists.”

Overall, Fauci’s response is consistent with mask-wearing guidance issued by the CDC at that point in time in February 2020, which was based on the limited knowledge that we had of the virus and its spread. Health authorities reversed their stance on mask-wearing later, because new evidence emerged showing that people not displaying symptoms can also spread the virus. Changing one’s stance in light of new evidence that contradicts one’s original position is part and parcel of the scientific process. Several published studies show that mask-wearing reduces the spread of viral respiratory illnesses like COVID-19.

Scientific evidence doesn’t support the claim that hydroxychloroquine is effective for COVID-19

The evidence:
The claim that hydroxychloroquine is effective against COVID-19 has been repeated often during the pandemic. However, scientific evidence provided by large-scale, randomized controlled clinical trials showed that these drugs don’t provide any meaningful benefit to patients, in terms of mortality and length of hospital stay, as earlier reviews by Health Feedback (here and here) explained.

The U.S. National Institutes of Health (NIH) conducted clinical trials on adults hospitalized with COVID-19 across 34 hospitals nationwide. A press release by the NIH stated that the “interim results showed the drug neither caused harm nor improved patient outcomes. The trial had enrolled 479 of the expected 510 patients”. The findings were published in JAMA[9].

The U.K.’s RECOVERY trial compared the outcomes for 1,542 patients treated with hydroxychloroquine and those of 3,132 patients who were given usual care only. A statement by the trial’s chief investigators after reviewing the data reported no significant improvement in 28-day mortality and “no evidence of beneficial effects on hospital stay duration or other outcomes”.

The investigators concluded that “These data convincingly rule out any meaningful mortality benefit of hydroxychloroquine in patients hospitalised with COVID-19.” Their findings were published in the New England Journal of Medicine[10].

The WHO’s Solidarity trial, which enrolled more than 11,000 adults in 30 different countries (among whom 954 were assigned to hydroxychloroquine treatment) also found no significant improvement in the mortality of hospitalized COVID-19 patients treated with hydroxychloroquine, when compared to standard of care. The findings were published in the New England Journal of Medicine[11].

What Fauci’s emails said:
Some alleged that Fauci’s emails showed he knew hydroxychloroquine worked for COVID-19. Articles by Gateway Pundit claimed that “millions died” because hydroxychloroquine was “disqualified” as a treatment by Fauci and that Fauci “lied to the public” although he knew of “hydroxychloroquine success in early 2020”. This claim commonly centers on an email exchange between pharmacologist Phillip Gatti and Fauci.

On 24 February 2020, Gatti sent Fauci an email asking “Is there any indication/data to substantiate this claim from China (attached publication) that chloroquine/hydroxychloroquine can decrease COVID-19 infections and lung disease?”

Fauci replied by saying: “There are no data in this brief report and so I have no way of evaluating their claim. There are a lot of these types of claims going around. I would love to see their data.”

Gatti followed up by writing that “There are data from 2005 showing inhibition of SARS infection and spread from 2005.” Gatti’s email was forwarded by Fauci to one of his advisors, with Fauci writing, “Let us discuss”.

It’s unclear exactly which publication Gatti referred to, but based on the subject line of the email (“chloroquine in COVID-19”) and the description of the study, it is very likely this one, published in August 2005[12]. The study examined the effect of chloroquine on the replication of the virus SARS-CoV-1 in cell cultures. This virus was responsible for the SARS outbreak in 2003.

The use of this study as the basis for the claim that hydroxychloroquine works isn’t new and was observed in April 2020. As explained in this previous review by Health Feedback, a significant limitation of the study was that it was conducted on cells growing in the laboratory, not in people. Human beings are far more complex than a group of cells growing in a Petri dish. Consequently, this study doesn’t provide evidence for the drug’s effectiveness in people.

On the other hand, as we explained above, we do have evidence about the effectiveness of hydroxychloroquine in people, thanks to large, randomized clinical trials around the world. And the data from these trials showed that the drug provides no meaningful benefit to patients in terms of mortality and length of hospital stay.

In summary, nowhere in Fauci’s emails is there evidence that hydroxychloroquine is effective for treating COVID-19, as some claimed. And the scientific evidence, gathered from COVID-19 patients in randomized controlled trials, doesn’t support the use of hydroxychloroquine for treating COVID-19, since it has thus far shown no beneficial effect.

Fauci’s emails don’t show he was given strong evidence that the virus was engineered

The evidence:
The different theories behind the origin of SARS-CoV-2 and the evidence for each theory were discussed in detail in a previous Insight article by Health Feedback. In brief, genomic and phylogenetic studies of the virus and its known relatives haven’t offered evidence supporting the claim that the virus was manmade.

Popular claims that the virus was engineered were based on various suppositions, such as SARS-CoV-2 being produced by genetically modifying another coronavirus, and that the virus contained genetic sequences from the human immunodeficiency virus. But these claims either failed to provide a plausible explanation for how such engineering was done or were based on spurious analyses, as these previous reviews by Health Feedback explained.

At the same time, there isn’t evidence to rule out the scenario that a naturally occurring virus escaped the laboratory. But it’s also important to remember that this isn’t the same as saying there is evidence showing that this happened.

Given the lack of evidence that allows us to accept or reject the hypothesis of a laboratory accident with a high degree of certainty, scientists called for “a proper investigation” into the matter in this letter published by Science on 14 May 2021:

We must take hypotheses about both natural and laboratory spillovers seriously until we have sufficient data. A proper investigation should be transparent, objective, data-driven, inclusive of broad expertise, subject to independent oversight, and responsibly managed to minimize the impact of conflicts of interest.

What Fauci’s emails said:
Several posts claiming that Fauci knew the virus was “likely engineered” cited an exchange between Fauci and Kristian G. Andersen, a professor of immunology and microbiology at Scripps Research Institute. Andersen studies the evolution of viruses.

On 31 January 2020, Andersen wrote to Fauci that “On a phylogenetic tree the virus looks totally normal and the close clustering with bats suggest that bats serve as the reservoir. The unusual features of the virus make up a really small part of the genome (<0.1%) so one has to look really closely at all the sequences to see that some of the features (potentially) look engineered.”

The latter part of Andersen’s statement was seized on by some as evidence that the virus was engineered, without accounting for the fact that Andersen had expressed uncertainty about this in the email:

But we have to look at this much more closely and there are still further analyses to be done, so those opinions could still change.

Indeed, Andersen and colleagues continued to study the genetic sequence of the virus. Their findings, published in Nature Medicine on 17 March 2020[13], concluded that “Our analyses clearly show that SARS-CoV-2 is not a laboratory construct or a purposefully manipulated virus.”

Andersen explained why he changed his mind regarding the question of whether the virus was engineered in this Twitter thread on 4 June 2021:

All the features in SARS-CoV-2 that, to us, suggested possible engineering were identified in related coronaviruses in the first half of 2020, which largely invalidated our preliminary hypothesis of engineering and instead bolstered the argument for a natural origin. In the days immediately following my email to Dr. Fauci, additional data was released (or we became aware of it), including the full genome of RaTG13.

He also went on to highlight that this change of mind was part and parcel of the scientific process:

This is a textbook example of the scientific method where a preliminary hypothesis is rejected in favor of a competing hypothesis as more data become available and analyses are completed.

Others cited an email sent by Adam Gaertner to Fauci, with the subject line “Coronavirus bioweapon production method”. Gaertner calls himself an “independent researcher”, although in this video, he stated that “I’m not treating people. I’m not a doctor, a professor, or anything else”, suggesting that he doesn’t hold credentials in biology or medicine.

Gaertner cited “intervirion fusion”, and then went on to copy, word for word, from the Methods section of a 2005 study published by researchers at the University of Pennsylvania[14].

One of the study’s co-authors, adjunct associate professor at the University of California Berkeley Graham Simmons, told USA Today that Gaertner misinterpreted it.

‘It really makes no sense that it could be a coronavirus bioweapon production method,’ Simmons, now a senior investigator at Vitalant Research Institute, said in an email. ‘I am happy someone made Tony Fauci aware of this work as it is a really cool experiment and was funded by NIH, but the misinterpretation is appalling.’

Paul Bates, a professor of microbiology at the University of Pennsylvania and another co-author of the study, pointed out that “are completely replication-defective, meaning they cannot produce [infectious] virus.”

In summary, Fauci’s emails don’t provide evidence that the virus was “likely engineered”. Studies of the virus haven’t yet shown signs of engineering, and the virus’ genome is consistent with a natural origin. However, the scenario that a naturally occurring virus escaped the laboratory remains a plausible one, although there also isn’t evidence showing that a lab escape did occur.

Most COVID-19 survivors develop immunity from a previous infection, but they can still benefit from vaccination

The evidence:
Natural infection does produce protective immunity in most cases, but reinfection can and does happen. This suggests that not all survivors develop protective immunity from infection alone. It’s unclear how many COVID-19 survivors experience reinfection, as there isn’t enough data to make conclusions, although reinfection is thought to be uncommon.

The emergence of variants is a source of uncertainty regarding the protection provided by natural immunity. A study estimated that as many as two-thirds of people in the city of Manaus, Brazil, were infected during the first wave of COVID-19[15]. Even though this might have been expected to provide some immunity in the majority of the population, the city suffered a second wave of COVID-19 cases worse than the first one. One potential contributing factor to the more severe second wave could be the Gamma variant, also called P.1 and first detected in Brazil, which may be more transmissible[16].

Vaccination can help enhance COVID-19 survivors’ protective immunity. Firstly, vaccine boosters designed to target variants can further improve the immune system’s ability to respond to an infection by a variant, as Cassandra Berry, a professor of immunology at Murdoch University, explained in this article published by The Conversation.

Secondly, individual variability in immunity can arise due to factors such as genetic susceptibility, age, and the amount of virus a person was exposed to (also known as infectious dose)[17]. Since vaccines are designed to produce optimal immunity, as Berry explained, vaccination can help to bridge the immunity gap in a survivor that didn’t generate protective immunity from infection alone.

The U.S. Centers for Disease Control and Prevention recommends COVID-19 vaccination, regardless of whether a person already had COVID-19.

Finally, some research suggests that one dose of vaccine in survivors produces an enhanced immune response strong enough to fight off variants[18,19], reported the New York Times.

What Fauci’s emails said:
Some claimed that Fauci’s emails prove that COVID-19 survivors have immunity to the virus. Fox News host Tucker Carlson went as far as to claim that this means survivors “don’t need to be vaccinated”. This claim is based on an email exchange between Fauci and Ezekiel Emanuel, an oncologist and chair of the Department of Medical Ethics and Health Policy at the University of Pennsylvania.

On 4 March 2020, Emanuel emailed Fauci asking if “a person is likely to be immune once they caught the coronavirus once? Do we know anything about likely drift?”

Fauci responded by saying “No evidence in this regard, but you would assume that [there] would be substantial immunity post infection. It is an RNA virus and so you can expect mutations, but not sure how much is going on. Will have to check.”

Developing some level of immunity following an infection is a well-established scientific observation, but as we explained above, individuals can vary significantly with regards to the level of immunity they develop and not everyone who was previously infected is protected from future infection.

As we can see, Fauci hedged on the subject in the email by stating that “substantial immunity” was an assumption and that there was “no evidence in this regard”. However, this nuance is lost in viral content asserting that Fauci already knew about immunity in survivors in March 2020. At that point in time, there was little to no evidence of how well survivors developed and retained immunity, given that it was the early days of the pandemic.

Emanuel’s question of “drift”, or antigenic drift—in which small mutations accumulate in a virus’ genome and change the virus’ properties—and Fauci’s response, suggests that early on, scientists already anticipated, based on existing knowledge of viral evolution, potential virus variants emerging. This could in turn affect how well existing immunity could fight off future infections.

In summary, Fauci’s emails don’t show that he knew about immunity in COVID-19 survivors, but postulated that this was likely. At that point in time, there was little data on the immunity that survivors developed. While most COVID-19 survivors do develop protective immunity, not all of them do. The emergence of virus variants may also affect the level of protection provided by immunity from natural infection. Vaccination can overcome these challenges and can therefore be beneficial even for people who already had COVID-19.


Overall, the various claims that some people have attempted to associate with Fauci’s emails have no factual basis and no basis in science.

Scientific studies showed that masks do reduce the spread of viral respiratory infections like COVID-19. Large randomized clinical trials studying the effectiveness of hydroxychloroquine in COVID-19 patients found that the drug didn’t offer any meaningful benefit to patients. Although there is scientific evidence showing that most people who had COVID-19 develop some level of immunity to the disease, individual variability in immunity and the emergence of virus variants means that vaccination can be beneficial even if a person already had the disease.

Finally, scientific studies of the virus’ genome to date haven’t shown evidence that the virus was engineered in a laboratory. At the same time, there isn’t evidence to rule out the scenario that a naturally occurring virus escaped the laboratory. However, this isn’t the same as saying there is evidence showing that this happened. At the moment, there is a lack of evidence that allows us to accept or reject the hypothesis of a laboratory escape with a high degree of certainty, and scientists are treating both a naturally occurring jump of the virus from animal to human (zoonosis) and laboratory escape as plausible scenarios.


USA Today compiled a timeline of events, explaining how Fauci’s public and private comments on face masks, hydroxychloroquine, and the origin of SARS-CoV-2, compare with each other.



Published on: 10 Jun 2021 | Editor:

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