2022-02-07-世界卫生组织-Weekly_epidemiological_update_on_COVID-19_-_8_February_2022_22页_2mb

COVID-19 Weekly Epidemiological Update Summary

Edition 78, published 8 February 2022

Global Overview

As of 6 February 2022, global COVID-19 cases dropped by 17% week-over-week, while deaths increased by 7%. Six WHO regions collectively reported over 19 million new cases and 68,000 new deaths. Cumulative figures stand at approximately 392 million cases and 5.7 million deaths worldwide.

Regional trends show varying impacts:

• The Americas (-36%) and Europe (-7%) experienced decreases.
• Southeast Asia (-32%), Africa (-22%), and the Western Pacific (-8%) saw reductions, though Southeast Asia reported a significant 67% increase in deaths.
• Asia (both Eastern Mediterranean and South-East Asia) recorded increases in cases, with the Eastern Mediterranean (+36%) highlighting concern due to a 45% rise in deaths.

Geographically, nations like the US, India, Germany, Brazil, and Mexico reported the highest case counts, while US, India, and Mexico also led in weekly deaths, although international platforms are tracking Omicron variants' global prevalence.

SARS-CoV-2 Variants of Interest and Concern

Omicron continues to dominate global spread (96.7% of sequenced samples recorded in the last 30 days). Previous variants (Alpha, Beta, Gamma, Delta) persist at low levels in all WHO regions.

Omicron Variant Characteristics:

• BA.1 and BA.2 lineages (subsets of Omicron) have been identified. BA.2 lacks key mutations found in earlier variants, potentially impacting diagnostic methods previously used for lineage detection.
• Countries observed shifts in Omicron lineage proportions and case incidence over mid-January onward. Increased testing capacity and timeline variability explain some discrepancies.

Vaccine Effectiveness (VE)
Evidence indicates that primary COVID-19 vaccines show diminished effectiveness against Omicron variants, particularly for preventing asymptomatic and mild infection. Protection against severe disease remains relatively higher but also declines over time.

Booster Doses:
Uptake of booster vaccines significantly increases VE against severe disease for all available vaccines, though this effect wanes over subsequent months.

WHO Regional Highlights

• Americas: Notable decreases in cases and deaths (-36% and 0%) but fluctuations at country level; the US, Brazil, and Argentina recorded substantial case numbers. Uganda recorded the biggest percentage drop in deaths.
• Africa: Continued decrease in cases (-22%) and deaths (-14%); South Africa noted increases in both.
• Eastern Mediterranean: Both cases (+36%) and deaths (+45%) increased. High infection rates observed in Iran, Jordan, and the Palestinian territories.
• Europe: Decline in cases (-7%) but an increase in deaths (+2%). France, Germany, and Russia reported the most new cases, while France, Italy, and Russia reported the highest death toll.
• South-East Asia: Decline in cases (-32%) but a sharp rise in deaths (+67%), attributed in part to date-back death reporting in India. India remains a primary driver of new cases.
• Western Pacific: Decrease in cases (-8%) and deaths (-5%); Japan and Australia recorded notable decreases.

Summary of Operational Updates

Recent activities include distribution of test kits, enhanced risk communication, increased vaccine pledges to Syria, leveraging flu surveillance for COVID tracking, and educational resources via WHO platforms.

Annex Notes

• All data provided is subject to verification and potential adjustments based on official reconciliations.
• Maps and summaries are updated when necessary due to data modifications.

Vaccine Effectiveness (VE) Notes

• Omicron: Reduced VE for both primary series and boosters against all outcomes, though slightly higher for severe disease.
• Delta: Available data previously indicated high VE for some vaccines against Delta after six months post-primary immunization, though effectiveness for infection decreases considerably.

This summary is derived from the official COVID-19 Weekly Epidemiological Update by the WHO, requiring fact-based reporting without analysis or speculation beyond the provided text.