2003-01-23-世界卫生组织-Weekly_epidemiological_record,_2003,_vol._78,_4_full_issue_8页_187kb

Document Summary: Weekly Epidemiological Record - 24 January 2003

Core Content

This document is the Weekly Epidemiological Record published by the World Health Organization (WHO) on 24 January 2003. It covers recent outbreaks and vaccine safety assessments, highlighting key public health actions and findings.

Outbreak News

1. Pertussis Outbreak in Afghanistan

• Context: An outbreak of pertussis was reported, prompting an emergency response.
• Action Taken: A multi-agency team (UN, WHO, Afghan Ministry of Health) is administering erythromycin to unvaccinated children in Khwahan and Darwaz districts.
• Treatment Regimen: A 10-day treatment is being given to all children under 15 years in 5 affected subdistricts.
• Coverage: 39 two-person teams are treating 100 children per day in 189 villages.

2. Yellow Fever Outbreak in Brazil

• Context: 24 cases and 5 deaths were reported from sylvatic yellow fever in Minas Gerais state.
• Case Details: 4 cases were laboratory confirmed, all occurring in a localized rural area.
• Response: The Ministry of Health and state health department are investigating the outbreak.
• Vaccination Campaign: A vaccination campaign has already begun.
• Monitoring: PAHO (WHO Regional Office for the Americas) is closely monitoring the situation and maintaining communication with the Ministry of Health.

Vaccine Safety Assessments

1. Global Advisory Committee on Vaccine Safety (GACVS)

• Established: In 1999 by WHO.
• Purpose: To address vaccine safety issues with scientific rigor and independence from WHO.
• Recent Meeting: Held in Geneva, Switzerland, on 16–17 December 2002.

2. MMR Vaccine and Autism

• Concerns: Raised in the late 1990s due to studies linking MMR vaccine to autism.
• Review Conducted: WHO commissioned an independent literature review on the association between MMR vaccine and autism.
• Findings: No evidence of a causal link between MMR vaccine and autism.
• Recommendation: No change in current vaccination practices with MMR vaccine.

3. Oculorespiratory Syndrome (ORS) Following Influenza Vaccination

• Description: A newly reported complication of inactivated influenza vaccine, first identified in Canada in 2000.
• Symptoms: Include red eyes, acute respiratory symptoms, and facial oedema.
• Timing: Symptoms typically appear 2–24 hours after vaccination.
• Risk Groups: More common in women and those over 40–59 years.
• Cause: Variations in virus particle disaggregation during manufacturing.
• Outcome: After manufacturing changes in 2001, fewer and milder cases were reported.
• Further Investigation: Needed for laboratory findings due to methodological limitations.

4. Hepatitis B Vaccination and Leukaemia

• Concerns: A potential link between hepatitis B vaccination at birth and acute lymphoblastic leukaemia.
• Findings: No convincing evidence of an association.
• Recommendation: No change in vaccination practices with the hepatitis B vaccine.
• Ongoing Research: Additional studies are being conducted by CDC and Vaccine Safety Datalink.

Accelerated Measles Control in Cambodia (1999–2002)

1. Background

• Context: Cambodia faced limited public health infrastructure due to over 20 years of civil war.
• Vaccination Start: 1986 with the Expanded Programme on Immunization (EPI).
• Early Challenges: Insecurity restricted EPI activities to Phnom Penh and Kandal Province until 1998.

2. Measles Control Program

• Objective: Reduce annual measles cases to <10,000 by 2005.
• Strategies: Strengthen surveillance, improve routine immunization, conduct supplementary immunization activities (SIAs), and provide vitamin A during outbreaks.

3. Vaccination Coverage

• Routine Vaccination: Increased from 34% in 1990 to 69% in 2000.
• SIAs: Initiated in December 2000 to cover children missed by routine services.

4. SIA Phases

• Phase I (Dec 2000–May 2001): Targeted <5-year-olds in remote border areas. Achieved 89% coverage.
• Phase II (Oct 2001–Apr 2002): Targeted 9 months to 14-year-olds in 8 provinces. Achieved 97% coverage.
• Phase III (Oct 2002–Apr 2003): Targeted 9 months to 14-year-olds in the remaining 7 provinces.

5. Implementation

• Teams: Composed of local, district, and provincial EPI staff, supervised by national program personnel.
• Approach: "Rolling" vaccination, with temporary posts in the morning and house-to-house visits in the afternoon.
• Social Mobilization: Conducted by local volunteers and community leaders to promote vaccination.

6. Surveillance and Outbreak Response

• Data Limitations: Pre-1999 data were limited.
• Outbreak Investigations: WHO supported 30 investigations in 1999, recording 1423 cases with a 1% case-fatality rate.
• Complications: 5.6% of cases showed vitamin A deficiency, and 0.4% developed encephalitis.
• Health Facility Use: Low due to traditional beliefs that children with measles should be kept at home.