by Jon Sanders
Research Editor and Senior Fellow, Regulatory Studies, John Locke Foundation
When Gov. Roy Cooper ordered everyone in North Carolina to wear face masks in June, he defended the order by citing reliance on “science and data.” His press office held that “Growing evidence shows that cloth face coverings, when worn consistently, can decrease the spread of COVID-19, especially among people who are not yet showing symptoms of the virus.”
Not even among or possibly among, but especially among people “not yet showing symptoms of the virus.” So Cooper forced mask-wearing on everyone under the notion that the most infectious people are the ones who feel perfectly well. Media and a fearful public went right along.
That makes the mask order like how Cooper turned the idea of quarantine upside down — ordering healthy people to “STAY AT HOME.” Quarantine had always been for the sick, not the healthy. Of course, back then Cooper had also told people it was for “thirty days … to slow the spread.”
Still, Cooper said that “North Carolina is relying on the data and the science.” I’ve already gone through the research used by the Cooper administration to justify ordering rather than urging voluntary adoption of face masks. Those studies were questionable and not very applicable to North Carolina — especially for use in issuing an executive order against people.
But there’s no science that supports this idea that asymptomatic people are the most infectious people. What research there is on the question of asymptomatic transmission is very limited and not at all what we’ve been led to believe.
According to guidance from the World Health Organization (WHO) published in June (weeks before Cooper’s mask order): “Current evidence suggests that most transmission of COVID-19 is occurring from symptomatic people to others in close contact, when not wearing appropriate PPE.” There are two main factors to pay attention to: symptomatic people and close contact.
What about people without symptoms? To be clearer, what about infected people without symptoms? (After all, nearly all the people you encounter without symptoms aren’t infected.)
WHO notes a “possibility of transmission” from people who are infected but haven’t developed symptoms (presymptomatic). Others never develop symptoms (asymptomatic). For either group, their ability to transmit the virus is speculative. It’s a presumed possibility on the basis of them having the virus. According to WHO (emphasis added here and in other quotations):
Viable virus has been isolated from specimens of pre-symptomatic and asymptomatic individuals, suggesting, therefore, that people who do not have symptoms may be able to transmit the virus to others. Comprehensive studies on transmission from asymptomatic individuals are difficult to conduct, but the available evidence from contact tracing reported by Member States suggests that asymptomatically-infected individuals are much less likely to transmit the virus than those who develop symptoms.
A possibility. It may be. But available evidence suggests asymptomatic people are “much less likely” to transmit the virus. These words are a far cry from “especially among.”
At the time of WHO’s guidance, available research was not only scant, but researchers couldn’t discount that the few suspected cases of asymptomatic transmission might owe to someone forgetting who else they came in contact with (“recall bias”) or to indirect transmission from what is called “fomite” transmission, which is “contact with surfaces in the immediate environment or with objects used on or by the infected person.” WHO reported:
Among the available published studies, some have described occurrences of transmission from people who did not have symptoms. For example, among 63 asymptomatically-infected individuals studied in China, there was evidence that 9 (14%) infected another person. Furthermore, among two studies which carefully investigated secondary transmission from cases to contacts, one found no secondary transmission among 91 contacts of 9 asymptomatic cases, while the other reported that 6.4% of cases were attributable to pre-symptomatic transmission.
The available data, to date, on onward infection from cases without symptoms comes from a limited number of studies with small samples that are subject to possible recall bias and for which fomite transmission cannot be ruled out.
Perhaps for those reasons the government of the Netherlands has resisted forcing citizens to wear face masks. In late July, Dutch Medical Care Minister Tamara van Ark explained, “From a medical point of view, there is no evidence of a medical effect of wearing face masks, so we decided not to impose a national obligation.”
In mid-August, Sweden’s chief epidemiologist, Dr Anders Tegnell, called the scientific case for wearing masks “astonishingly weak.”
Three new studies are out this month surrounding the issue of asymptomatic transmission. They offer little evidence for it beyond a conceptual possibility. None of them support the notion that asymptomatic individuals are the most infectious people from whom we “especially” need protection.
A study published August 6 in JAMA Internal Medicine found that swab and sputum tests on asymptomatic and symptomatic individuals revealed they had similar viral loads (viral RNA). On that basis authors called it a “biological plausibility” that asymptomatic individuals could transmit COVID-19 to others.
It’s important to note that the authors don’t go out on a limb with that plausibility. “Although the high viral load we observed in asymptomatic patients raises a distinct possibility of a risk for transmission, our study was not designed to determine this,” they wrote, adding shortly afterward, “It is important to note that detection of viral RNA does not equate infectious virus being present and transmissible.”
An article on this study by The New York Times talks with University of Hong Kong epidemiologist Benjamin Cowling, who thought the finding was important even as he was “circumspect” on asymptomatic transmission: “Because asymptomatic people do not cough or sneeze, he said, it is possible that they are less efficient than expelling the virus than those who are clearly unwell.”
A study also published this month in the journal Respiratory Medicine tracked 455 contacts of “Case A, “a 22-year-old female patient who had a medical history of congential heart disease (CHD).” Case A went to the emergency room with chest distress and worse shortness of breath than usual, but “without cough, sputum production and fever.” The diagnosis was “congenital heart disease, atrial septic defect and pulmonary hypertension.” As part of hospitalization, she was was given a nasopharyngeal swab to test for SARS-CoV-2 [i.e., COVID-19] infection, a test that came back positive despite her being — and remaining — asymptomatic for COVID-19.
The study routinely screened all of Case A’s contacts, including 224 hospital staff members, 35 nearby patients, and 196 family members. Median contact with family members was five days; nearby patients, four days; and hospital staff, “long exposure” except for “some doctors in other departments [brought in briefly] because of emergency consultation.” The study found that “All the 455 contacts were excluded from the SARS-CoV-2 infection,” reiterating “there had been no cases of infection in a relatively dense space.”
The researchers conclude that “Infectivity of some asymptomatic SARS-CoV-2 carriers might be weak.” They acknowledge the limitation of the study being that there was “only one case” and say “Large-scale multicenter studies” would be needed to test their conclusion.
Still, a feature of interest is their discussion of why their finding of zero infections among 455 contacts from an asymptomatic carrier could be possible in light of research finding similar viral loads in asymptomatic and symptomatic patients. It could be that Case A didn’t have a large viral load. It could also well be that asymptomatic patients aren’t coughing and sneezing:
In the light of “Zero infection” for this case, we venture to guess that the viral load of respiratory tract samples in the asymptomatic patient might not be high. Moreover, although pathogenic nucleic acids can be detected in respiratory tract samples from asymptomatic carriers, the opportunity of transmission is less than that in symptomatic patient owing to the absence of the way expelling pathogen via cough and sneezing.
Incidentally, the introduction to this study acknowledged that “Recent studies indicated that transmission of COVID-19 could also occur from individuals with no symptoms [10, 11]. However, for now, whether asymptomatic SARS-CoV-2 carriers are contagious still remain controversial.”
The citations are of a study that found one case out of 24 asymptomatic (or presymptomatic) COVID-19 patients who transmitted the virus to close contacts (immediate family members) and of an analysis that viral load detected in an asymptomatic patient “was similar to that in the symptomatic patients, which suggests the transmission potential of asymptomatic or minimally symptomatic patients.”
But a research question that “still remain[s] controversial” is not settled science, let alone scientific basis for an executive order against people.
A study published August 13 in the Annals of Internal Medicine evaluated the risk for transmitting COVID-19 to close contacts in different settings. This study monitored 3,410 close contacts of 391 people (“index cases”) with varying levels of infections (asymptomatic, mild, moderate, and severe).
The authors found that the more severe the index case of COVID-19, the greater the risk of transmitting to close contacts (the “secondary attack rate”). Severe or critical cases had a secondary attack rate of 6.2 percent (the confidence interval was between 3.2 and 9.1 percent). The transmission risk from moderate cases was 5.6 percent, and for mild cases, 3.3 percent.
For asymptomatic cases, the study estimated the transmission risk at 0.3 percent, with the confidence interval ranging from 0 percent to 1 percent. Again, that is a transmission risk for close contacts, not brief passers-by. As the authors wrote, “asymptomatic cases were least likely to infect their close contacts.”
The main findings were that “the secondary attack rate of COVID-19 was relatively low, and household contacts were at higher risk for infection” and that “patients with more clinically severe cases or those with symptoms were more likely to infect their close contacts.”
Concerning those results, the authors even noted that,
This supports the view of the World Health Organization that asymptomatic cases were not the major drivers of the overall epidemic dynamics.
There’s nothing scientific about quarantining the healthy or forcing them to wear face masks. Regardless, the Cooper administration and their sympathetic media have convinced fearful North Carolinians that the “science” tells us, basically, if you feel fine, you could be extremely infectious, the more so than if you were seriously ill.
The most reliable science on COVID-19 tells us that the more you’re in close contact with someone infected and symptomatic, and the more severe the case, the higher your risk of contracting it. On the other hand, your risk from a brief encounter with someone at a grocery store, someone walking from the door to the restaurant table, or someone going past on a public sidewalk is indistinguishable from zero.
We’re not getting that information from Cooper, DHHS Sec. Mandy Cohen, or the media they allow to participate. Instead, the message that folks are told is, You don’t wear the mask to protect yourself; you do it to protect others. The more panicked among us have turned that into, If you don’t wear a mask, you’re the reason people die!
This is how it’s come to be that the scariest figure in public imagination is a strong, fit, active person who looks and feels perfectly well but isn’t wearing a mask. The horror.