Recombinant Vaccines

Definition: A recombinant vaccine utilizes a subunit of the Ebola virus, which helps in immunization.
Common Vaccine Used: ERGTVA vaccine, also known as the Erglo vaccine.

Antigen Insertion: The vaccine leverages a common cold virus to carry Ebola proteins or antigens on its surface.
- Body's Response: The immune system recognizes the virus and begins to produce antibodies against the injected Ebola proteins, preparing for potential infection.

Initial Vulnerability: After vaccination, an individual remains vulnerable to Ebola for two weeks as the immune response builds.
Response Timeline: Immune response may begin within the first ten days, but full immunity generally develops around two weeks post-vaccination.

Eligibility: Initial vaccine approval was for individuals aged 18 and over; subsequently expanded to those aged one and older, provided they exhibit no symptoms.

Protection During Exposure: If vaccinated within a window prior to symptom manifestation, individuals have a good chance of protection against Ebola.

Duration of Protection: Uncertainty exists regarding the longevity of immunity (less than ten years post-introduction) and the potential need for boosters in the future.

Shedding of Virus: Following vaccination, individuals may shed the common cold virus via bodily fluids (saliva, urine), but this poses minimal risk to others due to the non-harmful nature of the carrier virus.
Risk Assessment: Unlike live Ebola virus shedding, the common cold virus presents negligible infection risk.

Unsuitable Populations: The vaccine's safety has not been evaluated in pregnant individuals or those who are immunocompromised.
- Compassionate Use Cases: Vaccination may still be considered under specific exposure circumstances for these groups.

Two-Dose Vaccine Option: Johnson & Johnson offers another vaccine requiring two doses, spaced eight weeks apart.
- Limitations in Emergencies: The extended timeline makes this option less practical during immediate outbreaks.
Efficacy Against Specific Strains: Both the Merck vaccine and the J&J vaccine are effective against the Zayer strain of Ebola; not effective against other strains like the Sudan strain.

Surveillance Impact: Ongoing surveillance of Ebola has improved understanding of outbreak dynamics and helped design effective control measures and therapies.

Multiple Pathways of Infection: Ebola's interaction with different biological pathways complicates treatment development but also informs prevention strategies such as PPE and quarantining.

Definition and Purpose: The strategy vaccinates individuals identified as primary and secondary contacts of an Ebola patient to contain outbreaks efficiently.
- First Ring: Includes individuals who had direct contact with a confirmed case.
- Second Ring: Includes people who interacted with those in the first ring, broadening the protective effort.
Voluntary Participation: Individuals choose to participate in vaccination; alternatives must be provided to non-participants (e.g., monitoring or quarantine).

Decision-Making in Outbreaks: Individuals must prioritize whom to vaccinate based on their potential risk for exposure and social roles in the community.
Role of Traditional Healers: Given their prominence in community health, their interactions may influence disease spread versus protection strategies.

Case Study: Discussion of a recent outbreak where caution was warranted due to misdiagnosis and unsafe burial practices in an Ebola context, which can exacerbate infections.
Wider Implications: Responses to past crises, such as the COVID-19 pandemic, illustrate complexities in vaccine rollout during public health emergencies.

Scenario Analysis: Participants role-play providing vaccines during simulated outbreak conditions, requiring strategic decision-making based on limited supply and exposure risks.
Factors to Consider: Includes individual roles, the nature of exposure, social responsibilities, and logistical challenges in outbreak scenarios.

Ongoing Research Needs: Continuous study required for vaccine durability, approval in vulnerable populations, and responses to emerging strains of Ebola.
Importance of Communication: Effective messaging to bolster community trust and compliance with health measures is crucial for successful vaccination strategies.