- Current situation unclear: cases rising in many countries, but vaccine efficacy against severe disease remains high.
- Potential double epidemic with flu, but flu cases currently low; vaccination can reduce unvaccinated by 25% in communities with 80% coverage.
- Ventilation and air purifiers (including simple filters) are effective in reducing transmission.
- Over 7 billion vaccine doses given; safety data overwhelming; vaccinated have lower all-cause mortality.
- Vitamin D deficiency worsens COVID-19 outcomes; supplementation recommended especially in winter.
- Vaccine protection against any infection wanes to <50% over time, but memory response prevents severe disease; 95% protection against hospitalization lasts at least 9 months.
- Vaccinated transmit virus less: 63% reduction in household transmission if infected.
- Long COVID prevention by vaccines is promising but data incomplete; media exaggerates prevalence.
- Boosters are highly effective, especially where initial doses were close together; Netherlands slow on Janssen booster.
- No major new variants; Delta subvariant emerging; vaccines effective against all variants so far.
- Rapid antigen tests are accurate for infectiousness; negative test indicates very low infectiousness; PCR tests measure different timeline.
- Immune measurement not useful for most; booster campaigns likely expand to all.
- Nasal vaccines and mRNA flu vaccines in development; pan-corona and universal flu vaccines show promise.
- Drugs: Remdesivir effective early but requires hospitalization; Molnupiravir (pill) reduces hospitalization by 50% if taken within 5 days; cost and safety concerns; Pfizer's pill in development.
- Encouraging vaccination remains key to reducing hospitalizations and protecting vulnerable.