2022-11-22-世界卫生组织-Weekly_epidemiological_update_on_COVID-19_-_23_November_2022_26页_2mb

报告摘要

New weekly cases globally decreased by 5% compared to the previous week, with 2.4 million new cases reported.
New weekly deaths decreased by 13%, with 7,802 reported fatalities.
Cumulative cases surpassed 634.8 million, and cumulative deaths reached 6.6 million globally.

Case numbers decreased or remained stable in five regions:
- Eastern Mediterranean: -22%
- Europe: -11%
- Africa: -9%
- Western Pacific: -4%
- Americas: +3%
South-East Asia saw an increase in cases by 8%.
Death numbers decreased or remained stable in four regions:
- Europe: -26%
- Eastern Mediterranean: -20%
- Americas: -11%
- Western Pacific: +1%
Africa and South-East Asia experienced significant increases in deaths, with +124% and +13%, respectively.

Highest new weekly cases:
- Japan: 593,075 (+18%)
- Republic of Korea: 364,536 (+2%)
- United States: 274,067 (-3%)
- France: 186,446 (+23%)
- China: 158,813 (-8%)
Highest new weekly deaths:
- United States: 2,202 (-5%)
- Japan: 702 (+27%)
- China: 476 (+16%)
- France: 441 (+9%)
- Russian Federation: 430 (-1%)

Omicron accounted for 99.9% of all reported sequences.
BA.5 and its descendants remain dominant, with 72.1% prevalence in epidemiological week 44.
BA.2 and its descendants had 9.2% prevalence, up from 6.4% in the previous week.
BA.4 continued to decline, from 3.6% to 3.0%.
BQ.1 and XBB (a recombinant of BA.2.10.1 and BA.2.75) were reported from 73 and 47 countries, respectively.
BQ.1 prevalence increased from 19.1% to 23.1%, and XBB from 2.0% to 3.3%.

BA.5 and its descendants continue to be the most prevalent.
BA.5.2, BA.5.2.1, BF.5 (BA.5.2.1.5), and BF.7 (BA.5.2.1.7) are the most common sublineages.
Over 500 sublineages of Omicron are currently in circulation.

Public Health Domain	Omicron (B.1.1.529)	BA.1	BA.2	BA.4	BA.5
Transmissibility	Higher than Delta	Lower than BA.2, BA.4, BA.5	Lower than BA.4, BA.5	Lower than BA.5	Higher than BA.1, BA.2, BA.4
Disease Severity	Lower than Delta	Similar to BA.2	Similar to BA.1	Lower or similar to BA.1, BA.2	Increased or similar to BA.1, BA.2
Risk of Reinfection	Reduced compared to naive individuals	Reduced after BA.2	Reduced after BA.1	Varying evidence	Varying evidence
Impact on Antibody Responses	Reduced neutralizing activity	Lower titers compared to index virus	Lower titers compared to index virus	Lower titers compared to BA.1	Lower titers compared to BA.1
Impacts on Diagnostics	PCR assays remain accurate; S gene target failure may be a proxy	S gene target failure	Majority S gene target positive	S gene target failure	S gene target failure
Impact on Treatments	No difference in antiviral effectiveness	Reduced neutralization activity of sotrovimab and casirivimab-imdevimab	Same as above	Same as above	Same as above

VE against severe disease remained higher than against symptomatic disease or infection.
mRNA vaccines (Pfizer BioNTech-Comirnaty, Moderna-Spikevax) had VE ≥ 70% in 67% of estimates for severe disease within the first six months.
Vector vaccines (AstraZeneca-Vaxzevria, Gamaleya-Gam-Covid-Vac, Janssen-Ad26.COV2.S) had VE < 70% for severe disease.
Inactivated vaccines (Sinovac-CoronaVac, Beijing CNBG-BBIBP-CorV) had VE < 70%, but ≥ 50% in some cases.

Substantially improved VE for all outcomes (severe disease, symptomatic disease, infection).
mRNA boosters showed VE ≥ 70% for severe disease in 87% of estimates.
VE against symptomatic disease and infection declined more rapidly than against severe disease.
Pfizer BioNTech-Comirnaty booster had VE > 70% against hospitalization, which waned to < 50% by six months.
VE against milder outcomes declined to < 50% within three months.

13 studies evaluated the absolute VE of a second booster, showing ≥ 70% for death, severe disease, symptomatic disease, and infection.
Relative VE of a second booster was higher for severe disease and death than for symptomatic disease and infection.
Interpretation of relative VE is complex due to varying absolute VE and epidemiological contexts.

Data interpretation should consider changes in testing strategies and surveillance systems.
Prevalence surveys indicate that reported cases may underestimate actual cases.
Omicron sublineages continue to evolve, with BQ.1 and XBB being of particular interest.
Variant-based vaccines have no VE data yet.
Data on long-term protection after booster doses is limited.