2022-01-09-世界卫生组织-COVAXIN®_BBV152_–_Inactivated,_COVID-19_vaccine_7页_202kb

Overview of COVAXIN® COVID-19 Vaccine

COVAXIN® (BBV152) is an inactivated SARS-CoV-2 vaccine developed by Bharat Biotech, designed to prevent COVID-19. It stimulates an immune response without causing disease by using an inactivated virus, and includes aluminum-based adjuvant to enhance immunity and 2-phenoxyethanol as a preservative for stability. WHO recommends it for individuals aged ≥18 years.

Mechanism of Action

The vaccine presents inactivated SARS-CoV-2 to the immune system, prompting antibody production for protection against infection. Clinical trials demonstrate its ability to prepare the body to respond to live SARS-CoV-2 exposure.

Efficacy

A Phase 3 trial (≥18 years) showed:

• 78% efficacy against any COVID-19 case 14+ days post-second dose.
• 93% efficacy against severe COVID-19.
• Age-specific efficacy: 79% for <60 years, 68% for ≥60 years.
• 64% efficacy against asymptomatic infection, with a median follow-up of 99 days.
  WHO determines the benefits outweigh risks.

Administration

• Dose and Interval: Two doses of 0.5 mL each, administered at least 4 weeks apart. If the second dose is given earlier than 4 weeks, it does not need repetition; if delayed, administer as soon as possible.
• Route and Site: Intramuscular injection in the deltoid muscle.
• Recommended Age: ≥18 years; both doses should use the same product. Same product is preferred for immunocompromised individuals.

Special Populations

• Comorbidities: Vaccination is recommended for conditions like cardiovascular disease, diabetes, etc., as it reduces severe COVID-19 risk.
• Elderly (≥60 years): Recommended due to higher severity risk, with maintained safety.
• Pregnant Women: Vaccination is advised if the benefits outweigh risks, with no delaying pregnancy or testing recommended.
• Immunocompromised: Requires an extended primary series with a third dose (at least 1 month post-second, within 3 months). Immune response may be reduced.
• HIV Patients: Vaccination is possible if on stable antiretroviral therapy, with data limitations on benefits.
• Other Groups: Co-administration with other vaccines is potential, but requires at least 14 days interval. Booster doses' timing is under assessment.

Safety and Side Effects

• Common Events: Local: pain at injection site; systemic: fever, fatigue, headache, myalgia.
• Allergic Reactions: Rare anaphylaxis; individuals with known allergies should be monitored (15-30 minutes post-vaccination).
• Precautions: Vaccination can be postponed for acute severe febrile illness or confirmed COVID-19. Otherwise, continue standard COVID-19 measures post-vaccination.

Storage and Handling

• Temperature: Store between +2°C and +8°C, undiluted, not frozen. Protect from light.
• Multi-Dose Vials: Discard unused vaccine 6 hours or end of session first; update expiry date if using post-puncture.
• Wastage: Dependent on country context; dispose per local guidelines.

Variants and Other Considerations

• Variant Effectiveness: Efficacy against Delta, Kappa variants remains robust, with trials including variant infections. WHO recommends use regardless of variants, with ongoing monitoring needed.
• Immunity Testing: Antibody tests may detect past infection or vaccination; nucleic acid tests are unaffected by vaccination.
• Ongoing: Parvovirus was assessed via VVM, with studies planned for pregnant women to gather more data.
• Resources: WHO recommendations and background details are available at: WHO websites listed in content.

This vaccine is part of global efforts to control COVID-19, with WHO endorsing its use based on trial data and ongoing surveillance.