2021-03-19 General


Well, that’s depressing. A paper in The Lancet reports on a mathematical model which says that vaccination without pharmaceutical measures (e.g. masking, keeping 2m apart, etc) is likely to only bring R down to 1.58. Translation: vaccination alone won’t get rid of the virus.

However, this smells off to me. Measles has an R0 of 12 to 18, and the measles vaccine has an efficacy of about 93%. If we can suppress measles, we’ve got to be able to suppress COVID-19 (R0 of ~3.5, vax efficacy of ~95%).

There’s a preprint which reports that the efficacy of one shot for cancer patients is a lot lower than for healthy patients. Two shots does give them good efficacy.

I remind you of a paper which showed the vaccine wasn’t as effective in obese people (even at a second dose) (though this calls the study into question). I also could have sworn that I saw a paper which said that one shot is not as effective in older people as it is in younger people, but I can’t find it. (I did find this which says AZ is only 60-70% effective in people over 70 after only one shot.)

It makes me think that we should not wait too long to give a second dose for cancer patients, the obese, and the elderly.

More depressing thoughts! The vaccines are not approved for kids yet, and if kids can be a reservoir, this article points out that that means essentially everybody else (well, 96% of people in the US) will need to get vaccinated. That article says that only about 58% of people in the US say they will get vaccinated. That doesn’t look good for the US. We might have a closed border for a looooooong time. 🙁

Contact Tracing

There’s an interesting case study of a transmission chain in New Zealand, verified by genomic analysis.

  • One of patients A or B was infected in India and transmitted it to the other, possibly in-flight.
  • Patient A or B infected Patient C in-flight.
  • Patients A, B, C, D, and E arrived and went into quarantine at a quarantine hotel.
  • Patients D and E, who were in the room next to Patient C, tested negative.
  • Patient C opened their hotel door (to get food or something), then closed it.
  • 50 seconds later, the door to Patient D and E’s room opened. In that 50 seconds, D and E caught COVID-19 from Patient C. Review of corridor video showed this was the only time they had anything approximating contact with Patient C. The hotels rooms did have positive pressure.
  • Patient C was found to be infected and moved off of that floor into a different isolation unit.
  • Patients D, E, and G took a flight to Christchurch. Patient G caught COVID-19 from sitting (masked) right in front of D and E (also masked).
  • Patients D and E also passed it on to a household member (Patient F).
  • Patient G passed it on to household members (Patients H and I).

I found this interesting for two reasons:

  1. D and E caught it from a different hotel room 50 seconds after that door had closed.
  2. New Zealand is really diligent about keeping the virus out of the country! Good on them!

The End

The pandemic feels different to me now. It feels like people are looking forward to a visible end to the pandemic, instead of floating in a fear of an indefinite future. I’m seeing a lot of articles which are looking at the pandemic in almost a retrospective way. Partly that’s because we just passed the one-year milestone of people realizing that shit got real, but partly also because the vaccinations are going really well in the US and to a lesser extent in Canada.

Apparently I’m not the only one who has noticed: the Washington Post has an article which reports that people are starting to buy clothes and shoes again!