2023-12-01 General


This preprint from USA (2023-11-08) discussed a small study with 16 Long COVID patients who had small fiber neuropathy verified by skin biopsies. Eight of the patients got intravenous immunoglobulin and saw big improvements.

This paper from Pakistan (20231122) found that people who were fully vaccinated were 62% less likely to get Long COVID as those who were unvaccinated.

This case study from USA describes three people with bad Long COVID (including crushing fatigue) who all had unexpected remission within a week after casirivimab/imdevimab monoclonal antibody infusions.

I want to take a moment to recap anecdotal Long COVID cures (as opposed to drugs you have to keep taking). These have been backed up by case studies, but usually not randomized controlled trials:

  • Monoclonal antibody infusions (above).
  • Stellate ganglion block for taste/smell loss. (This one actually does have a randomized controlled trial and seems to work really well.)
  • Nicotine patches.
  • BC007 (a DNA-based aptamer that binds to and neutralizes functional autoantibodies against G protein-coupled receptors).

(You can see the full list of references to these studies over on my Treatments page.)

This is encouraging! I want to see more randomized controlled trials!


This paper says that RATs are now so inaccurate — “Recent research has found multiple commonly-used rapid antigen tests to now have diagnostic sensitivities below 30 % for previously vaccinated or infected, with even lower sensitivities the first 48 h of infection” — that they might do more harm (in terms of false confidence that you aren’t infected) than good.

I knew that RATs gave a lot of false negatives, but I didn’t realize how bad it had gotten.

  • This paper from the USA (20220615, i.e. Omicron timeframe) says that for asymptomatic college athletes, BinaxNow (which is the US version of the BC “green box” tests) only accurately said someone was positive 39.2% of the time. 🙁
  • This paper from Germany (20230810) tested a bunch of different European RATs against BA.4/5 and got pretty abysmal results: most were at around 30% able to spot positive people, but some were way down at the 20% level.
  • This paper from USA (20230704) found that on the first day a PCR tested positive, RATs only found 9.3% of asymptomatic cases.

If RATs are no good, what can you do? This blog post talks about different Nucleic Acid Amplification Tests (NAAT) tests which you can (allegedly) buy now. Some are only available in the USA, and I haven’t found a vendor for Lucira (except for places selling old ones which are about to expire). (Ed: I have ordered myself some Metrix tests from the USA.)


Someone posted on Mastodon that they were frustrated that nobody was gathering information on COVID-19 treatments, especially on mouthwashes. I was skeptical that mouthwashes could help: there’s still going to be virus in the nose and lungs. However, they pointed me at a paper from Spain (2022-03-25) which looked at a dentist’s office. They had identical HEPA air purifiers running for three months in the waiting room and in the three treatment rooms, and had patients gargle with a dilute hydrogen peroxide solution immediately upon entering a treatment room (and removing the mask they had been wearing in the waiting room). They then sampled the HEPA filters and found COVID-19 in the waiting room’s filter but not in any of the treatment rooms’ filters!

There are other papers (like here and here) which say that povidone iodine mouthwash/gargle reduces the viral load in the mouth. Here and here are review articles which talks about other mouthwash types’ effectiveness. (Spoiler: most work, and hydrogen peroxide looks like it is probably best.)


Good news! This preprint from USA says that the new XBB 1.5 booster works very well against not just XBB, but against most of the other major circulating lines. (It does not mention BA.2.86, however, which is making gains in the USA.)

This paper from Switzerland (20231129) found that anti-COVID IgG antibodies in the nose were higher for people who had been vaccinated than those who had only been infected. Unfortunately, IgG wasn’t what mattered: when they took anti-COVID IgA antibodies out of nasal fluid, the ability of the nasal fluid to neutralize SARS-CoV-2 plummeted.

This study from USA (20231201) found that two or more vaccines were 40% effective against Emergency Department visits or hospitalization in children under 5.

Mitigation Measures

This paper from Germany (20230730) found that putting HEPA air purifiers in kindergartens didn’t reduce COVID-19 infection rates. The infection rate was actually higher for kids in classrooms with the air purifiers, even though the viral load was measured to be significantly lower. The authors suggest that spread is mostly from close interaction where the air passes between kids before it can get to an air purifier; they also suggest that having the air purifiers could have led to a false sense of security.

This review of research (20231123) from 1970 to 2022 didn’t find that air purifiers helped reduce infectious diseases.

However, this article from Finland (20231117) says that air purifiers in daycares led to ~30% reduction in sick days for both children and staff and this (paywalled) article (20231020) says that air purifiers cut sick days by 20% at primary schools in England.

Further ideas for why some research shows air purifiers don’t help might be kids mostly getting infected outside their classrooms with nice clean air; it might be that the air purifiers are underpowered or poorly placed.

Meanwhile, this paper from Italy (20230325) found that increasing classroom ventilation to 4.67-6.66 room air replacements per hour gave an 82% reduction in COVID-19 cases in schoolchildren.

Increasing ventilation also reduces the amount of virus in the air, but presumably it also generates stronger air currents which maybe whisk the virions away faster?


I have tended to think that outdoors is magic, but it is possible to catch COVID-19 outdoors. In addition to a superspreader event at a Chinese night market which I mentioned before, this paper from Spain (20220228) found that people who attended one of two outdoor music festivals were about 1.5 to 2 times as likely as matched controls to get COVID-19. Note that the music festivals started in the afternoon but went into the wee wee hours of the morning, while the night market was also, well, at night. (Yes, sunlight kills viruses.)

Recommended Reading

There’s a rash of hospitalizations of kids with pneumonia in places in both China and the USA. This blog post says it’s more likely that there are more susceptible kids around than that COVID-19 damages the immune system. She notes, for example, that this paper which found that kids who had COVID-19 infections are more susceptible to RSV might just be finding that kids who are more susceptible to COVID are also more susceptible to RSV. On the other hand, this article says that COVID-19 has damaged our immune system.

I found this report on pandemic funerals — both disruptions and workarounds — oddly comforting to me.