Transmission of coronaplague among the fully masked Japanese

“Dynamic Change of COVID-19 Seroprevalence among Asymptomatic Population in Tokyo during the Second Wave” (medRxiv):

Objective: To assess changes in COVID-19 seroprevalence among asymptomatic employees working in Tokyo during the second wave. Design: We conducted an observational cohort study. Healthy volunteers working for a Japanese company in Tokyo were enrolled from disparate locations to determine seropositivity against COVID19 from May 26 to August 25, 2020. COVID-19 IgM and IgG antibodies were determined by a rapid COVID19 IgM/IgG test kit using fingertip blood. Across the company, tests were performed and acquired weekly. For each participant, serology tests were offered twice, separated by approximately a month, to provide self-reference of test results and to assess for seroconversion and seroreversion. Setting: Workplace setting within a large company. Participants: Healthy volunteers from 1877 employees of a large Japanese company were recruited to the study from 11 disparate locations across Tokyo. Participants having fever, cough, or shortness of breath at the time of testing were excluded. Main Outcome(s) and Measure(s): Seropositivity rate (SPR) was calculated by pooled data from each two-weeks window across the cohort. Either IgM or IgG positivity was defined as seropositive. Changes in immunological status against SARS-CoV-2 were determined by comparing results between two tests obtained from the same individual. Results: Six hundred fifteen healthy volunteers (mean + SD 40.8 + 10.0; range 19-69; 45.7 % female) received at least one test. Seroprevalence increased from 5.8 % to 46.8 % over the course of the summer.

COVID-19 infection may have spread widely across the general population of Tokyo despite the very low fatality rate.

In other words, nearly half of this (masked) population came up positive for antibodies to COVID-19. That’s after excluding anyone with symptoms.

If masks are effective when used by the general public, how did the world’s most competent and experienced users of masks end up transmitting this virus to each other at these rates?

8 thoughts on “Transmission of coronaplague among the fully masked Japanese

  1. You miss the point. “Viral load” is a big issue. Viral infections are a race between the germ and the immune system. If the dosage is low at initial exposure, the virus gets much less of a head start and there is a better chance the case will be asymptomatic. Masks don’t eliminate how many germs you breathe in but they reduce the load.

    • How do you know that people didn’t take off their masks when they were indoors around other people that they knew? Masks may help strangers from giving it to each other in crowded, indoor place like a train (and may, to your point, reduce viral load in those settings) but how can we rule out that the majority of spread here could have occurred during people getting together with friends and family when masks are typically taken off?

    • @Joseph will it ever be OK to not wear a mask again? Masks will prevent people from inadvertently inhaling EEE infected mosquitos…

    • As mentioned in the article, the commentary published in NEJM that poses this theory seems to be based on two studies, one of which was conducted on hamsters in China. I would love to know how the hamsters were “dosed” with coronavirus as they frolicked behind surgical mask barriers! If the surgical mask barrier allowed the hamsters to get “just enough” covid-19 to contract it but not so much that they got seriously sick, perhaps this could pave the way for an easy vaccine (just slap on a surgical mask and breathe in enough ‘covid’ air to induce an immune response). 🙂

      On a more ‘serious’ note, in this article, the concept of population-wide immunity is not pooh-poohed but embraced (or at least accepted as a simple fact of any epidemiological curve): “Researchers say that any public health strategy that helps reduce the severity of the virus – such as mask wearing – should increase population-wide immunity as well.” Maybe that could be the all clear for when we can stop wearing masks: when a region has reached 60-70% seroprevalence? Japan seems quite close to getting there.

  2. Viral load… Plenty of studies done on that. But of course that’s the kind of logic anti maskers simply don’t understand. I don’t really care whether people wear them or not, just stop with the bullshit claims against them.

  3. Masks Reduce Viral Load Enthusiasts: If you’re right, why drag out the “light load immunity development” for several years, as the U.S. is doing by combining masks with shutdown? Why not fill sports stadiums with (a) sick people who can cough out virus unmasked, and (b) healthy people who will wear masks and absorb healing immunity-building light viral loads? After a couple of weeks of this, how could coronavirus possibly thrive in the U.S.? Also, reopen workplaces, gyms, schools, etc., and actively encourage anyone who is sick to continue coming in amongst the masked healthy.

    (Separately, if masks and feverish sanitizing and most-things-shut-down work, why is there a raging common cold epidemic in Boston right now? How did the cold virus manage to get through all of these barriers we’ve set up?)

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