Lunchtime pandemic reading.
Standard disclaimer: this is a roundup of informative pieces I've read that interest me on the severity of the crisis and how to manage it. I am not a qualified medical expert in ANY sense; at best I am reasonably well-read laity. ALWAYS prioritize advice from qualified healthcare experts over some person on Facebook.
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There appears to be a relationship between severity of COVID-19 and antibody decay. "The protective role of antibodies against SARS-CoV-2 is unknown, but these antibodies are usually a reasonable correlate of antiviral immunity, and anti–receptor-binding domain antibody levels correspond to plasma viral neutralizing activity. Given that early antibody decay after acute viral antigenic exposure is approximately exponential,3 we found antibody loss that was quicker than that reported for SARS-CoV-1,4,5 and our findings were more consistent with those of Long et al.1 Our findings raise concern that humoral immunity against SARS-CoV-2 may not be long lasting in persons with mild illness, who compose the majority of persons with Covid-19. It is difficult to extrapolate beyond our observation period of approximately 90 days because it is likely that the decay will decelerate.3 Still, the results call for caution regarding antibody-based “immunity passports,” herd immunity, and perhaps vaccine durability, especially in light of short-lived immunity against common human coronaviruses. Further studies will be needed to define a quantitative protection threshold and rate of decline of antiviral antibodies beyond 90 days."
Source: https://www.nejm.org/doi/10.1056/NEJMc2025179
Commentary: The tricky part of this disease is that antibody equation. If people who had little to no impact from the disease - mild cases - are showing very low antibody concentrations, then there may a possibility that they could contract it again. Lots more research needs to be done to determine how probable this is, but at the least, it means that just because you've had COVID-19 does not mean you should forego wearing a mask, watching your distance, or washing your hands. Play it safe.
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Viral loads vary wildly from person to person, depending on their activities. "In this modeling study, breathing and coughing were estimated to release large numbers of viruses, ranging from thousands to millions of virus copies per cubic meter in a room with an individual with COVID-19 with a high viral load, depending on ventilation and microdroplet formation process. The estimated infectious risk posed by a person with typical viral load who breathes normally was low. The results suggest that only few people with very high viral load pose an infection risk in poorly ventilated closed environments. These findings suggest that strict respiratory protection may be needed when there is a chance to be in the same small room with an individual, whether symptomatic or not, especially for a prolonged period."
Source: https://jamanetwork.com/journals/jamanetworkopen/fullarticle/2768712
Commentary: The study goes into exquisite depth, but the gist is this: enclosed airspaces are really, really bad news. We still don't know what level of viral load is needed to catch the disease, but we sure do know how fast we can spread it. Here's the important takeaway: heavier-than-average air usage activities like talking, singing, yelling, and coughing, as well as heavy breathing under duress (i.e. fitness and athletics) drastically increase the amount of virus a contagious person sheds. Thus, while we should all be wearing masks all the time out of the home, any enclosed environment where there's any amount of heavier-than-average air usage pose an increased risk, even outside. Jogging right behind someone? Even with a mask on, that person is just going to exhale more, period
The rule of thumb I've taught my family is to imagine everyone has a lit cigarette. If you're at a distance where you could smell them smoking, you're at a distance where you're in their airspace. Another rule of thumb is talking. If you can hear a person clearly, you're in their airspace. Being in other people's airspaces is something to minimize right now.
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The Lancet on aerosols. "The global pandemic of COVID-19 has been associated with infections and deaths among health-care workers. This Viewpoint of infectious aerosols is intended to inform appropriate infection control measures to protect health-care workers. Studies of cough aerosols and of exhaled breath from patients with various respiratory infections have shown striking similarities in aerosol size distributions, with a predominance of pathogens in small particles (<5 μm). These are immediately respirable, suggesting the need for personal respiratory protection (respirators) for individuals in close proximity to patients with potentially virulent pathogens. There is no evidence that some pathogens are carried only in large droplets. Surgical masks might offer some respiratory protection from inhalation of infectious aerosols, but not as much as respirators. However, surgical masks worn by patients reduce exposures to infectious aerosols to health-care workers and other individuals. The variability of infectious aerosol production, with some so-called super-emitters producing much higher amounts of infectious aerosol than most, might help to explain the epidemiology of super-spreading. Airborne infection control measures are indicated for potentially lethal respiratory pathogens such as severe acute respiratory syndrome coronavirus 2.
Some surgical masks might offer respiratory protection compared with not wearing a mask. Filtering facepiece respirators offer more respiratory protection than surgical masks, and powered air purifying respirator (PAPRs) hoods offer the best protection for most health-care settings.
Face shields can help decrease exposures to and contamination from large particle aerosols, but they do not offer inhalation protection against small particle aerosols.
PAPRs have built-in eye protection. Surgical masks and other respirators require a face shield or goggles to protect the eyes to prevent infection."
Source: https://www.thelancet.com/journals/lanres/article/PIIS2213-2600(20)30323-4/fulltext
Commentary: A few key takeaways. First, healthcare workers in high-risk settings need the best gear possible, and that means full face-plate protection in powered respirators.
Second, note that the Lancet is recommending eye protection. If you know for sure you are going into a COVID-positive environment, add a sealing eye protection mechanism like goggles to your personal protective equipment. An N95 mask coupled with goggles should offer sufficient protection - be sure to minimize the amount of time you spend in a COVID-positive environment.
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A study on transmission in flight. "The 44-year-old man was chatting with his wife and son on a flight from Singapore to China earlier this year when he let his guard down, allowing his face mask to slip below his nose.
That lapse appears to have been how he became infected with Covid-19.
The case, cited in a recently published study of an outbreak among passengers on a January flight, is one of the first to document a probable transmission on an airliner and is reviving calls for government rules requiring masks. It comes as safety concerns raise questions about whether passengers will return in sufficient numbers to keep airline companies from collapsing.
Lawmakers and airline unions -- which have sought more rigorous standards for months as infections surge across the nation and reports circulate of passengers skirting existing rules -- said the study adds new weight to their demands.""
Source: https://www.bloomberg.com/news/articles/2020-07-28/mask-advocates-cite-plane-transmission-study-in-call-for-mandate
Source: https://www.sciencedirect.com/science/article/pii/S1477893920303124
Commentary: Airplane air is recirculated but also filtered; however, if enough infected people are present, there may be enough aerosols present to infect nearby passengers with or without air filtration.
If you have to travel by plane, wear a sealing respirator and do not remove it for any reason from the moment you leave your own airspace (your home/car) until you arrive at your final destination airspace (hotel room, etc.). Don't take it off on the plane, in an Uber, in the hotel lobby, etc. Don't eat, drink, etc. - anything that would require taking off your protective equipment. If you have a medical condition that requires you to do so, consider alternate methods of transportation or delaying your travel.
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A reminder of the simple daily habits we should all be taking.
1. Wash/sanitize your hands every time you are in or out of your home for any reason. Consider also spraying the bottoms of your shoes with a general disinfectant (alcohol/bleach/peroxide) when you return home. Remember that cleaners are never to be ingested or injected.
2. Wear gloves and a mask when out of your home. Respirators are back in stock at online retailers, too.
3. Stay home as much as possible. Minimize your contact with others and maintain physical distance of at LEAST 6 feet / 2 meters. Avoid indoor places as much as you can; indoor spaces spread the disease through aerosols and distance is less effective at mitigating your risks.
4. Get your personal finances in order now. Cut all unnecessary costs.
5. Replenish your supplies as you use them. Avoid reducing your stores to pre-pandemic levels in case an outbreak causes unexpected supply chain disruptions.
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Common misinformation debunked!
There is no genomic evidence at all that COVID-19 arrived before 2020 in the United States and therefore no hidden herd immunity:
Source:
There is no evidence SARS-CoV-2 was engineered, nor that it escaped a lab somewhere.
Source: https://www.washingtonpost.com/world/2020/01/29/experts-debunk-fringe-theory-linking-chinas-coronavirus-weapons-research/
Source: https://www.nature.com/articles/s41591-020-0820-9
Source: https://www.nationalgeographic.com/science/2020/05/anthony-fauci-no-scientific-evidence-the-coronavirus-was-made-in-a-chinese-lab-cvd/
There is no evidence a flu shot increases your COVID-19 risk.
Source: https://www.factcheck.org/2020/04/no-evidence-that-flu-shot-increases-risk-of-covid-19/
Source: https://academic.oup.com/cid/advance-article/doi/10.1093/cid/ciaa626/5842161
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A common request I'm asked is who I follow. Here's a public Twitter list of many of the sources I read.
https://twitter.com/i/lists/1260956929205112834
This list is biased by design. It is limited to authors who predominantly post in the English language. It is heavily biased towards individual researchers and away from institutions. It is biased towards those who publish or share research, data, papers, etc. I have made an attempt to follow researchers from different countries, and also to make the list reasonably gender-balanced, because multiple, diverse perspectives on research data are essential.