The Expert Committee on COVID-19 Vaccination (EC19V) recommends that all vaccinated persons aged 18 years and above should receive a booster vaccine dose at about five months after the last dose of their primary vaccine course, or as soon as possible thereafter, in order to maintain good protection against COVID-19. This booster dose should not be delayed beyond nine months after the primary vaccine course.
2. Local and international data show reduced vaccine protection against COVID-19 infection from around six months after completion of the last vaccine dose in the primary vaccination series or earlier. The level of protection drops even further over time. There is also some reduction in protection against severe disease, particularly in older persons. In addition, international studies have shown that the protection against Omicron variant infection by a primary vaccination series is weaker compared to previous variants, and that boosters increase the protection against infection and severe illnesses caused by Omicron. As such, booster vaccination is crucial to ensure continued protection against COVID-19.
Booster Recommendation for Persons Vaccinated with the mRNA Vaccines
3. EC19V therefore recommends that those aged 18 years and above who have completed a primary course comprising two doses of either the Pfizer-BioNTech/Comirnaty or the Moderna COVID-19 vaccine should receive a booster dose of either mRNA vaccine around five months after the second dose, or as soon as possible thereafter. This booster dose should not be delayed beyond nine months after the primary vaccine course.
Booster Recommendation for Persons Vaccinated with the Sinovac-CoronaVac and Sinopharm Vaccines
4. Persons who had received two or more doses of the Sinovac-CoronaVac or Sinopharm vaccines as part of a three-dose primary vaccination series are strongly recommended to receive one dose of an mRNA vaccine as a booster dose. Such persons who received an mRNA vaccine as their third dose should do so around five months thereafter. However, those who received the Sinovac-CoronaVac or Sinopharm vaccine as their third vaccine dose should do so at three months thereafter, due to lower antibody levels generated by the third vaccine dose.
Booster Recommendation for Non-mRNA Vaccines
5. Individuals who have received recognised primary vaccination regimens other than the vaccines mentioned above are also recommended to receive a booster dose around five months, or as soon as possible thereafter. This includes persons who had completed the primary series vaccination with other WHO EUL vaccines.
Booster Recommendations for Recovered Persons and Persons with Medical Conditions Requiring an Enhanced Primary Series of Three mRNA Vaccine Doses
6. Persons with medical conditions such as moderate or severe immunocompromise, and who have received an enhanced primary series of three doses of an mRNA vaccine, are recommended to receive a booster dose (i.e. fourth dose) of an mRNA vaccine around five months after the third dose.
7. Persons who have recovered from COVID-19, and who were unvaccinated or partially vaccinated before their infection should receive one dose of the mRNA vaccine at least three months after infection to reduce their risk of reinfection. There is no change from previous recommendations for this group. No subsequent doses of vaccination are recommended at this time, but recommendations may be updated, as more data become available.
8. Persons who were fully vaccinated with two doses of mRNA vaccine and are not immunocompromised, who subsequently were infected with COVID-19 and recovered, also do not require an additional booster dose at this time. There is no change from previous recommendations for this group.
9. The Sinovac-CoronaVac vaccine should only be considered as a booster vaccine in persons who are medically ineligible to receive mRNA vaccines. All other persons should be boosted with the mRNA vaccines.
10. Timely booster vaccination will ensure optimal protection against COVID-19, including the Omicron variant. EC19V urges all persons aged 18 years and above to receive their booster vaccination as soon as they are eligible to do so.
EXPERT COMMITTEE ON COVID-19 VACCINATION
5 JANUARY 2022