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COVID-19 vaccinations in adolescents and children (COVAC Study)

The COVID-19 pandemic has caused more than 100 million cases and 3 million deaths globally, and over 10,000 cases in Hong Kong. The virus may cause long COVID and multisystem inflammatory syndrome in children. Some emerging virus variants have also been found to be more infectious to teenagers. Children and adolescents under 20 years old are contagious, and infected children may spread the virus to their grandparents. The prolonged suspension of classes and social distancing have also had a negative impact on students. Therefore, children and adolescents urgently need to be immunised against COVID-19.

The Department of Paediatrics and Adolescent Medicine and School of Public Health at HKUMed are now launching the COVID-19 Vaccination in Adolescents and Children (COVAC) study. Timely local data on the reactogenicity and immunogenicity of COVID-19 vaccines in adolescents and children will inform the public and the government whether the vaccines should be given to children, and allow complete school reopening as soon as possible. This study has been approved by the Institutional Review Board of HKU/Hospital Authority HK West Cluster.

Current COVID vaccines are given by an injection in the muscle. Yet, experience with inactivated flu vaccine suggests intradermal route (in the skin) vaccination may result in superior immunogenicity. There is currently no evidence on effectiveness of intradermal administration of COVID vaccines. 

In Hong Kong those below 12 are not allowed to receive CoronaVac yet. In the fully enrolled COVA study, adolescent participants were given CoronaVac via intramuscular route. In extension, we would like to recruit more healthy adolescents aged 3-17 for intradermal vaccination in the COVAC study. 

For more information, please fill in the form and researchers will contact you later.


2019冠狀病毒病(COVID-19)大流行在全球造成超過1億宗病例, 300多萬人死亡,而在香港亦有高達1萬多宗病例。兒童感染新冠病毒後可能會導致後遺症和多系統炎症綜合症。有些變種病毒也發現對青少年有更大的感染力。此外,20歲以下的兒童和青少年有較高的傳染性,在家感染同住長者的情況不容忽視。長時間的停課和社交隔離措施亦已對學生造成不良的影響。 因此,兒童和青少年急需接種新冠病毒疫苗。

港大醫學院兒童及青少年科學系以及公共衞生學院現正開展兒童及青少年新冠病毒疫苗研究(COVAC)。 有關COVID-19疫苗在青少年中的反應原性和免疫原性的本地數據,將適時通知公眾和政府,以決定應否把疫苗接種組別擴大至兒童,令學生可以早日復課。此研究已獲香港大學/醫管局香港西聯網研究倫理委員會批准。

現時COVID-19疫苗的接種都是通過肌肉注射途徑進行。 然而,根據滅活流感疫苗的研究經驗表明,皮內途徑接種疫苗可能會產生更好的免疫原性。 但目前仍沒有證據表明皮內注射COVID-19疫苗的有效性。

香港12歲以下 人士暫時未能接種科興(克爾來福)COVID-19疫苗。透過參與我們的COVA研究,部分青少年已通過肌肉注射途徑獲得COVID-19疫苗,名額已滿。我們另外希望招募更多3-17歲的健康兒童和青少年進行皮內注射科興(克爾來福)疫苗的COVAC研究。




Content | 研究內容

COVAC will recruit 200 healthy adolescents and patients with immune disorders aged 3 years or above. At the moment, the families will be offered to receive SinoVac's CoronaVac, by intradermal vaccination (for those aged 3-17) or intramuscular vaccination (aged 3-10). Participants will report adverse reactions and other adverse events following immunisation, and be followed up for immunogenicity assessments and vaccine breakthrough COVID-19 over a period of 3 years. Participants are covered by the Hong Kong government’s COVID-19 vaccine indemnity fund.

Interested parents may watch our study introduction video above.





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