2021-08-23-世界卫生组织-COVID-19_Vaccine_Moderna_mRNA-1273_7页_182kb

COVID-19 Vaccine Moderna Summary

Overview

The COVID-19 Vaccine Moderna is an mRNA-based vaccine (mRNA-1273) approved for use against COVID-19. Developed by Moderna Biotech, it received WHO Emergency Use Listing (EUL) on 30 April 2021. The vaccine instructions showed 94% efficacy in clinical trials among participants with no prior SARS-CoV-2 infection, based on a two-month median follow-up. WHO recommends it for individuals aged 18 years and older, with no upper age limit.

Schedule and Administration

• Recommended for adults aged 18 and above.
• Requires two doses of 0.5 mL each (100 μg per dose), with an ideal interval of 28 days between doses.
• If the second dose is administered earlier than 28 days, it does not need repetition. If delayed, it should be given as soon as possible, with a possible extension up to 42 days under certain conditions.
• Both doses must be from the same product to ensure protection. Heterologous schedules with other vaccines may be considered if the specific vaccine is unavailable, supporting similar or superior immunogenicity.
• Administered intramuscularly into the deltoid muscle. No diluent is required; vaccine is ready to use after thawing.

Storage and Stability

• Store in a freezer at -25 to -15°C in original carton; avoid dry ice or ultra-low temperatures.
• Unopened frozen vial shelf life: from receipt to expiration date.
• Unopened thawed vial at +2 to +8°C: up to 30 days, protected from light.
• Thawed punctured vial: usable for up to 6 hours after first dose withdrawal.
• Do not refreeze thawed vials. After first use, keep open vials at 2–8°C for up to 6 hours or end of session, whichever comes first.

Contraindications and Precautions

• Contraindicated in individuals with known history of anaphylaxis to any component, particularly polyethylene glycol (PEG), and those who experienced anaphylaxis after the first dose.
• Precautions: Conduct risk assessments for individuals with prior anaphylaxis to vaccines or injectables. Food, seasonal, or contact allergies (e.g., eggs, gelatin) are not contraindications. Postpone vaccination for acute severe febrile illness, acute COVID-19, or specific post-treatment with monoclonal antibodies for 90 days.
• Anaphylaxis risk exists; vaccination should occur in settings equipped for immediate treatment, with post-vaccination observation for at least 15 minutes (30 minutes for those with history of allergic reactions). Routine antipyretics or analgesics should not be prophylactically used.

Special Populations

• Pregnancy: Recommended if benefits outweigh risks; vaccine-elicited antibodies may protect infants. Not recommended for pregnancy testing or delaying pregnancy due to vaccination.
• Lactation: Similar efficacy expected; no recommendation to discontinue breastfeeding.
• Immunocompromised: Vaccination is recommended if not live virus, but data are insufficient for some; individual benefit-risk assessment needed, especially for HIV-positive individuals with poorly controlled therapy.
• Other Settings: Prioritize vaccination in high-density populations (e.g., refugee camps) where distancing is challenging.

Side Effects and Safety

• Common side effects (≥1/100–<1/10): Headache, nausea, myalgia, and injection site reactions (pain, swelling).
• Less common (≥1/1000–<1/100): Injection site itching.
• Rare (≥1/10000–<1/1000): Facial swelling, Bell’s palsy.
• Very rare (outside trials): Myocarditis and pericarditis observed more in younger men, post-second dose. Anaphylaxis is a known hypersensitivity event.
• General: Benefits outweigh risks, similar reactogenicity to other vaccines.

COVID-19 Variants

• Reduced neutralization activity observed against some variants like Beta, but maintained protection against severe disease hospitalization by some data. Efficacy against Delta is unknown; WHO recommends coordinated variant surveillance.

Important Reminders

• Continue COVID-19 prevention measures (masking, distancing) post-vaccination.
• Test for COVID-19 before vaccination if symptomatic; offer vaccination after recovery.
• Booster doses not recommended or required yet; timing to be evaluated based on data.
• Extend inter-dose interval in low-coverage, limited-supply settings up to 12 weeks to maximize first-dose impact.
• Use in occupational groups should consider potential work absence due to side effects.

Resources and Testing

• Use SARS-CoV-2 nucleocapsid protein tests for evidence of prior infection, not antibody tests for post-vaccination immunity assessment.
• Prior vaccination does not affect diagnostic tests for acute infection.