Analysis and comparison of chickenpox outbreaks in two schools at different educational stages: a mixed retrospective observational study – BMC Infectious Diseases

Report on Varicella-Zoster Virus: Epidemiology, Control Strategies, and Alignment with Sustainable Development Goals

Introduction: Varicella as a Global Public Health Concern

Varicella (chickenpox), caused by the Varicella-Zoster Virus (VZV), remains a significant global health issue, primarily affecting children but with potential for severe complications across all age groups. Effective management and prevention of varicella are critical for advancing public health and are directly aligned with the United Nations’ Sustainable Development Goal 3 (SDG 3): Good Health and Well-being. This report synthesizes epidemiological data and control strategies to underscore the importance of integrated public health initiatives in combating this infectious disease.

Epidemiological Landscape and Surveillance

Global Transmission Dynamics and Outbreak Characteristics

Understanding the transmission patterns of VZV is fundamental to achieving SDG 3, Target 3.3, which aims to end the epidemics of communicable diseases. Surveillance data reveals distinct epidemiological characteristics globally.

• Seroprevalence Studies: Research in regions like Germany and China has established baseline seroprevalence data, crucial for assessing population immunity and tailoring vaccination strategies. Studies in Harbin and Jiangsu Province, China, have provided detailed analyses of antibody levels across different age groups.
• Outbreak Settings: Varicella outbreaks are frequently documented in settings with high population density, such as schools and kindergartens. Reports from Beijing, Shanghai, and Shenzhen in China highlight the persistent challenge of controlling transmission in educational environments.
• Vulnerable Populations: Outbreaks among vulnerable groups, including Venezuelan immigrants in Brazil and refugees in Greece, underscore the intersection of public health with SDG 10: Reduced Inequalities. These situations call for equitable access to healthcare and preventive measures for displaced and marginalized communities.

Vaccination: A Cornerstone of Prevention and Control

Effectiveness of Immunization Programs

Widespread vaccination is the most effective tool for preventing varicella, directly supporting SDG 3, Target 3.8, which advocates for universal access to safe and affordable vaccines. The World Health Organization (WHO) has provided position papers guiding global vaccination policies.

1. One-Dose vs. Two-Dose Schedules: Numerous studies, including matched case-control analyses in Qingdao, China, have evaluated the comparative effectiveness of one-dose versus two-dose vaccine regimens. Evidence consistently demonstrates that a two-dose schedule offers superior protection, reducing the incidence of breakthrough infections.
2. Post-Exposure Prophylaxis (PEP): The use of the varicella vaccine for emergency PEP has proven instrumental in controlling outbreaks, as documented in studies from Guangzhou and Shanghai. This strategy is vital for mitigating the spread of the virus once an outbreak is identified.
3. Universal Vaccination Programs: The implementation of universal vaccination programs, such as the one assessed in Toscana, Italy, has led to a significant decline in varicella incidence, demonstrating the profound impact of systematic immunization on public health outcomes.

Challenges in Vaccine Efficacy

Despite high vaccination coverage, challenges remain that require ongoing research and strategic adaptation.

• Breakthrough Varicella: Cases of varicella in vaccinated individuals, known as breakthrough infections, continue to occur. Research has focused on identifying the clinical characteristics and risk factors associated with these cases to refine vaccine strategies and public health messaging.
• Vaccine Failure Rates: Studies have investigated the failure rate of the varicella vaccine during outbreaks, providing critical data for improving vaccine effectiveness and understanding the dynamics of waning immunity.

Integrated Strategies for Disease Prevention

Enhancing Health Education and Hygiene

Comprehensive control of varicella extends beyond vaccination and requires a multi-faceted approach that aligns with broader sustainable development objectives.

• Health Education in Schools: National school-based trials in China emphasize the importance of enhancing health education on infectious diseases. This contributes to SDG 4: Quality Education by empowering children and adolescents with the knowledge to protect their health and the health of their communities.
• Hygiene Practices: Promoting practices such as hand hygiene, as studied in programs in Guatemala, is a simple yet effective measure that complements vaccination efforts and supports SDG 6: Clean Water and Sanitation.

Modeling and Outbreak Management

Advanced analytical tools and robust management protocols are essential for an effective public health response.

1. Dynamic Modeling: The use of SEIR (Susceptible-Exposed-Infectious-Recovered) dynamic models helps in researching and determining optimal strategies for the prevention and control of varicella outbreaks in school settings.
2. Surveillance Systems: Continuous surveillance of varicella outbreaks, as conducted in sentinel jurisdictions in the United States, is crucial for monitoring vaccine effectiveness and adapting public health strategies in real-time, thereby strengthening the resilience of community health systems as envisioned in SDG 11: Sustainable Cities and Communities.

Conclusion: A Unified Approach to Achieve Sustainable Health Outcomes

Controlling varicella is a clear and achievable public health goal that contributes directly to the 2030 Agenda for Sustainable Development. By strengthening vaccination programs, ensuring equitable access for all populations, enhancing health education, and maintaining robust surveillance systems, nations can effectively reduce the burden of varicella. These integrated efforts not only protect individuals from a preventable disease but also build resilient health systems, promote health equity, and advance the overarching goal of ensuring healthy lives and promoting well-being for all at all ages (SDG 3).

Analysis of Sustainable Development Goals in the Article

1. Which SDGs are addressed or connected to the issues highlighted in the article?

The provided article, which consists of a list of references from a research paper, primarily addresses issues related to public health, infectious diseases, and vaccination. Based on the titles of the cited works, the following Sustainable Development Goals (SDGs) are relevant:

• SDG 3: Good Health and Well-being: This is the most directly relevant SDG. The entire list of references focuses on the epidemiology, prevention, and control of varicella (chickenpox), a communicable disease. The articles discuss vaccination effectiveness, outbreak management, and public health strategies, all of which are central to ensuring healthy lives and promoting well-being for all at all ages.
• SDG 4: Quality Education: This goal is indirectly connected. Numerous references specifically mention varicella outbreaks in schools, kindergartens, and universities (e.g., References 10, 14, 17, 29, 36). Infectious disease outbreaks in educational settings disrupt learning, cause absenteeism, and can lead to school closures. Therefore, controlling these outbreaks is essential for maintaining a safe and consistent educational environment.
• SDG 10: Reduced Inequalities: This goal is relevant as several references highlight the impact of varicella on vulnerable populations. For instance, Reference 18 discusses a chickenpox outbreak among Venezuelan immigrants in shelters, Reference 33 examines outbreaks in refugee camps, and Reference 12 focuses on vaccination in less developed regions. These studies underscore the health disparities faced by marginalized and displaced populations, linking disease control to the broader goal of reducing inequality.

2. What specific targets under those SDGs can be identified based on the article’s content?

Based on the themes in the reference list, several specific targets under SDG 3 can be identified:

1. Target 3.3: By 2030, end the epidemics of AIDS, tuberculosis, malaria and neglected tropical diseases and combat hepatitis, water-borne diseases and other communicable diseases.
   • Explanation: Varicella (chickenpox) is a highly communicable disease. The references are dedicated to understanding and controlling it. For example, Reference 3 analyzes the “Epidemiological characteristics of varicella Outbreaks-China, 2006–2022,” and Reference 16 explores “optimal strategies for prevention and control of varicella outbreak.” This research directly contributes to the goal of combating communicable diseases.
2. Target 3.8: Achieve universal health coverage, including financial risk protection, access to quality essential health-care services and access to safe, effective, quality and affordable essential medicines and vaccines for all.
   • Explanation: A significant portion of the cited research revolves around the varicella vaccine. References assess the “Effectiveness of varicella vaccine” (Reference 9), compare “one-dose versus two-dose varicella vaccine” strategies (Reference 27), and evaluate “universal varicella vaccination program[s]” (Reference 22). This focus on vaccine effectiveness, accessibility, and optimal administration strategies is fundamental to achieving universal access to essential vaccines.
3. Target 3.d: Strengthen the capacity of all countries, in particular developing countries, for early warning, risk reduction and management of national and global health risks.
   • Explanation: The article references studies on public health surveillance and emergency response. Reference 5 discusses “varicella public health emergency events,” Reference 36 focuses on “Varicella outbreak surveillance in schools,” and Reference 4 highlights the role of “emergency vaccination.” This body of work aims to improve the systems for monitoring, reporting, and responding to disease outbreaks, thereby strengthening national health security and risk management capacities.

3. Are there any indicators mentioned or implied in the article that can be used to measure progress towards the identified targets?

The article’s references do not state official SDG indicators, but they strongly imply the use of specific public health metrics that serve as de facto indicators for measuring progress:

• Indicator for Target 3.3 (Implied): Incidence of Varicella.
  • Explanation: Progress in combating communicable diseases is measured by their incidence. The references frequently use terms like “outbreak,” “incident,” and “epidemiology.” For example, Reference 4 mentions the goal of “declining chickenpox incident.” Tracking the number, size, and frequency of varicella outbreaks serves as a direct measure of how effectively the disease is being controlled.
• Indicator for Target 3.8 (Implied): Varicella Vaccination Coverage Rate.
  • Explanation: To achieve universal health coverage for vaccines, it is essential to measure the proportion of the population that has been vaccinated. The articles discuss vaccine effectiveness in “a highly-vaccinated school population” (Reference 17) and compare one-dose vs. two-dose vaccine effectiveness (Reference 27). These analyses rely on data about vaccination coverage to draw conclusions, making it a critical implied indicator.
• Indicator for Target 3.d (Implied): Capacity for Public Health Surveillance and Response.
  • Explanation: The ability to manage health risks can be measured by the effectiveness of surveillance and response systems. The studies on “outbreak surveillance” (Reference 36), “post-exposure prophylaxis” (Reference 9), and management of “public health emergency events” (Reference 5) are all components of this capacity. The existence and quality of such research and programs indicate a country’s preparedness for health emergencies.

4. Table of Findings

Source: bmcinfectdis.biomedcentral.com