Transmission
This article has some really cool pictures of some really really cool science. The study authors made a chemical/mechanical computer model of a virion inside an aerosol with water, lung fluid, mucous, and other crap that somebody might breathe out — 1.3 BILLION atoms worth — and then simulated it every millionth of a second!
They found that the positively-charged virion attracted negatively-charged mucins (pieces of the mucous lining), and the mucins helped shield it from damage from the calcium ions jetting around, and also helped keep the virion from poking out of the aerosol molecule.
Delta is more positively charged than Alpha; Omicron is more positively charged than Delta. It might be that Omicron is more infectious in part because it survives in aerosols for longer.
This article reports that they have found COVID-19 in deer in Canada.
Vaccines
Speaking of computer models, this study made a model of several adenoviruses used in vaccines (e.g. AZ and J&J) and confirmed that the adenoviruses could form stable compounds with PF4, a protein involved in the clotting problem sometimes seen with adenovirus vaccines.
This preprint found that vaccine effectiveness against infection after two doses of Pfizer started at 81% for 14-73 days after dose2, but dropped to 46% after six months. 14-73 days after dose2 of AZ, the effectiveness against infection was about 50% and just kind of stayed there.
This Letter to the Editor found that male professional basketball players with Alpha and Delta infections didn’t have meaningful differences in infection duration, viral load, or symptom severity. They did find a slightly higher number of peak viral loads over a threshold for Delta breakthrough infections vs. Alpha breakthrough infections, but that might have been due to small sample sizes. Infections were cleared in a average of 5.5 days in men who had been vaccinated than in unvaccinated (average of 7.5 days).
This paper (from a UBC/UToronto study!) found that antibody levels were higher in adult paramedics who got two doses of mRNA at a longer interval (6-7 weeks) than at a shorter interval (3-4 weeks).
Recommended Reading
This article talks about efforts to make a pandemic treaty, enforceable under international law.