Cobovax study
Randomized trial of COVID-19 booster vaccinations [Cobovax study]
「互苗」研究計劃
新冠疫苗加強劑隨機試驗「互苗研究計劃」
Study Introduction
This is an open-label clinical trial on COVID-19 vaccine booster in Hong Kong organized by the School of Public Health, the University of Hong Kong. Hong Kong citizens aged 18 or above who have already received two doses of BioNTech or Sinovac at least 6 months ago are invited to participate in this research study. We will randomly allocate each eligible participant to a third dose of mRNA vaccine (BioNTech) or inactivated vaccine (Sinovac), allowing us to compare the differences between mix-and-match versus same-technology third doses, for example in terms of enhancing immunity against COVID-19 or reactions after vaccination. Then, we will track these participants for a period of 1 year (2021 – 2022) to monitor the post-vaccination reactions and immune protection after receiving COVID-19 booster vaccination.
研究簡介
這是一項在香港本地進行的有關新冠病毒(COVID-19)疫苗加強劑的開放標籤臨床研究計劃,由香港大學公共衞生學院主辦,邀請香港18歲或以上、在6個月前已完成接種兩劑復必泰或科興疫苗的市民參加。本研究計劃會為合資格參與者隨機接種第三劑mRNA疫苗(復必泰)或滅活疫苗(科興),以比較接種混合類型疫苗對比接種同類型疫苗在如提升抵抗新冠肺炎免疫水平或接種疫苗後反應的差異。接著,我們將追踪參加者1年 (2021 – 2022),以全面監測接種新冠疫苗加強劑後的接種反應及免疫保護。
Enrolment Eligibility
You may be eligible to join the study if you meet the following criteria:
  • 18 years old or above
  • Have received two doses of BioNTech (Comirnaty) OR two doses of Sinovac (CoronaVac), with the most recent dose at least six months (180 days) prior to enrolment
  • Willing to provide blood samples
You are not eligible to join the study if you meet any of the following criteria:
  • A history of confirmed COVID-19 infection
  • Have received any type of COVID-19 vaccines other than Comirnaty or CoronaVac before
  • You received the previous first and second dose of COVID-19 vaccine 43 days or more apart
  • Have allergies to the active substance or other ingredients of mRNA or inactivated COVID-19 vaccines
  • Have any medical condition related to the immune system as determined by a clinician
  • Use of medication that impairs immune system in the last 6 months, except topical steroids or short-term oral steroids (course lasting 14 days or less)
  • Have used any blood products within the past 90 days
  • Currently pregnant, or planning for lactation or to become pregnant in the coming 3 months
During the online registration and subsequently before enrolling to the study, our team will have more detailed assessment with you to see whether you are suitable to join this study.
參加資格
若您符合以下納入條件,您或符合參與本研究資格:
  • 18歲或以上人士
  • 曾在至少6個月(180天)前接種了兩劑復必泰或科興疫苗
  • 願意提供血液樣本
若你符合以下任何條件,即不適合參與本研究:
  • 曾確診感染新冠病毒(COVID-19)
  • 曾接種除了復必泰或科興疫苗以外的任何其他新冠疫苗
  • 您已接種的第一劑及第二劑新冠疫苗相隔43日或以上
  • 對mRNA新冠疫苗或滅活新冠疫苗之活性成分或其他成分過敏
  • 有被醫生診斷與免疫系統相關的任何醫療狀況
  • 在過去6個月內曾使用抑制免疫系統的藥物,外用類固醇或短期口服類固醇(療程持續14天或以下)除外
  • 在過去90天內曾使用任何血液製品
  • 正在懷孕,或計劃於未來3 個月內懷孕或哺乳
在填寫網上登記表格時及在之後被納入本研究前,本團隊將會和您進行更詳細的評估以判斷您是否適合參與本研究。
Importance
COVID-19 is caused by infection with the SARS-CoV-2 coronavirus, which has caused millions of deaths and major economic impacts worldwide since the beginning of 2020. Since 2021, different countries or regions around the world including Hong Kong have been offering free COVID-19 vaccination to the public with different types of COVID-19 vaccines. Due to differences in vaccine design and composition, these different COVID-19 vaccines could be different in terms of the ability to stimulate different branches of immune responses.
The emergence of variants of concern (VOCs) and observed decrease in vaccine-induced immune responses within few months after vaccination have suggested the potential need for booster vaccination in the near future. However, so far there are only very limited data on the immunogenicity and safety of a booster (third) dose of COVID-19 vaccination. Also, only limited studies evaluate the use of a different vaccine platform as a 3rd “booster” dose to a homologous 2-dose regime. However, this regime could have advantages – research suggest that using mRNA vaccine as a booster to inactivated vaccines may enhance the immune response when compared to using inactivated vaccine as the booster and, increase vaccine effectiveness; and could also allow a flexible immunisation deployment given distribution challenges of vaccines at a global scale. Therefore, there is an urgent need to conduct this research to help scientists design better vaccine deployment strategy against the emerging VOCs.
This study has been approved by the Institutional Review Board of the University of Hong Kong/ Hospital Authority Hong Kong West Cluster (UW21-492).
重要性
COVID-19由感染SARS-CoV-2冠狀病毒(新冠病毒)所引起,自2020年初起已於全球造成數百萬的死亡和重大的經濟影響。世界各地包括香港於2021年起為大眾免費接種不同種類的COVID-19疫苗。基於不同設計及成分,這些不同種類的COVID-19疫苗對刺激不同免疫系統反應的能力也可能各有不同。
新冠病毒「值得關切的變異株」(VOCs)的出現,及數據顯示接種疫苗後的免疫水平在數月內下降,反映短期內有可能需要考慮接種疫苗加強劑。然而到目前為止,關於接種COVID-19 疫苗加強劑(第三劑)的免疫原性和安全性的數據非常有限。再者,只有少數研究評估以基於不同設計的疫苗作為同源兩劑(homologous 2-dose)疫苗的第三(加強)劑。然而,這種方案有其優勢 – 研究提出以mRNA疫苗作為滅活疫苗的加強劑可進一步提升疫苗的免疫原性,並從而提高其疫苗有效性;及提供靈活的免疫接種計劃以面對疫苗供應全球性的挑戰。因此,我們有迫切需要進行是項研究,幫助科學家設計針對新發變異株更好的新冠疫苗接種策略。
本研究已獲得香港大學及醫管局港島西醫院聯網研究倫理委員會的審批(UW21-492)。
Procedure
計劃流程

1.
If you are 18 years old or above, have received two doses of Sinovac (CoronaVac) or BioNTech (Comirnaty) 180 days ago, and interested to receive a 3rd booster dose of either an inactivated vaccine (CoronaVac) or a mRNA vaccine (Comirnaty) now

complete a simple online registration form
(Click “Join Now” )

 

2.
Research personnel conduct initial screening on enrolment eligibility

 

3.
Research personnel arrange a face-to-face interview with you for further assessment

 

1.
如您是18歲或以上人士、曾在至少180天前接種兩劑復必泰或科興疫苗、及有興趣現在接種一劑第三(加強)劑滅活疫苗(科興)或mRNA新冠疫苗(復必泰)

完成簡單網上問卷登記
(按此「立即參加」)

2.
研究人員就參與資格進行初步篩選

3.
研究人員聯絡您安排會面作進一步評估

4.
During the interview, research personnel explain the details of the study to you and confirm your participation

 

5.
Upon enrolment to the study, you will be randomised to receive either a (booster) dose of inactivated vaccine (CoronaVac) or mRNA vaccine (Comirnaty)

 

6.
During the study period, regular follow-up activities include questionnaires and blood collection

 

4.
於會面期間,研究人員為您講解研究內容並確認參與

5.
納入研究時,您將會被隨機分配接種一劑(加強劑)滅活疫苗(科興)或mRNA新冠疫苗(復必泰)

6.
於研究期間,定期跟進包括問卷調查及抽血

No cost will be incurred for joining this study. To appreciate your support for our study, you will receive tympanic thermometer/ supermarket coupons during each regular follow-up for sample collection. In addition throughout the study, we may occasionally send you the results of your laboratory testing or findings of the study as a whole.

參與此研究費用全免。為答謝參加者對本研究的支持,參加者在每次定期跟進提供樣本後會獲贈耳探體溫計/超級市場禮券。另外於研究期間,研究團隊亦會不時向參加者發報其個人的檢測報告或本研究的整體研究結果。

How to Join
  • Click “Join Now” to complete a simple registration form online
    • Due to popular demand, we aim to complete initial screening on enrolment eligibility and get back to you within two weeks after registration
  • Call our study hotline during office hours
報名方法
  • 按此「立即參加」進行簡單網上登記
    • 報名反應熱烈,我們目標兩星期內回覆參於資格初步篩選結果
  • 於辦公時間內致電本研究熱線

Contact the research team

Cobovax study

School of Public Health, The University of Hong Kong

Phone/WhatsApp: +852 9446 3186

Email: cobovax@hku.hk

Office hours: Monday to Friday, 10am to 5pm (except public holidays)

聯絡研究團隊

「互苗」研究計劃

香港大學公共衞生學院

電話 / WhatsApp:+852 9446 3186

電郵:cobovax@hku.hk

辦公時間:星期一至五,上午十時至下午五時(公眾假期除外)

Results

Pending

研究結果

待定

The Science

About Coronavirus Disease 2019 (COVID-19)

The recent emergence of the new coronavirus disease 2019 (COVID-19) in late 2019 and the subsequent global pandemic has since caused millions of deaths and significant economic impacts globally. COVID-19 is caused by the infection of SARS-CoV-2 coronavirus where disease severity varies widely, from asymptomatic infection, mild self-limiting disease with common respiratory symptoms, to severe disease requiring hospitalization that may lead to long-term symptoms or death.

About COVID-19 Vaccine

COVID-19 vaccination could provide protection against SARS-CoV-2 infection or severe disease after infection, and would also help to reduce community transmission by the accrual of population immunity. Due to different vaccine formulations, different COVID-19 vaccines such as inactivated virus vaccines (e.g. Sinovac, Sinopharm), mRNA vaccines (e.g. BioNTech, Moderna) and non-replicating adenovirus-vector-based vaccines (e.g. Oxford–AstraZeneca, Johnson & Johnson, Sputnik V) may have different capacities to stimulate different branches of immune responses (e.g.  humoral, cell-mediated and innate immunity) and require different vaccination frequencies. Like other vaccines, mild allergic reactions (side effects) such as mild fever, swelling or pain at injection site, or, in rare cases severe allergic reactions, may occur after COVID-19 vaccination.
For more information about COVID-19 vaccines, please visit the official website of the Hong Kong government’s COVID-19 Vaccination Programme.

About vaccine booster shots

When we say “booster shots” for the current COVID-19 vaccination program, most usually refer to getting a third dose after an individual has received two prior doses of COVID-19 vaccination. Some reasons that may prompt individuals to consider receiving a third dose of COVID-19 vaccine include:
  1. in some more vulnerable groups such as immuocompromised individuals, compared to otherwise healthier individuals, the previous two doses of vaccination have not activated strong enough protective immune responses
  2. in any individuals, immune responses after vaccination may decrease over time naturally
  3. some COVID-19 vaccines may perform less well against new emerging virus strains
Preliminary data suggest the use of a same-technology (homologous) or a different-technology (heterologous) third dose using either Comirnaty or CoronaVac are safe, and data from other vaccine platforms suggest reactions after the third dose may be even less than that after the first dose. It is foreseeable that the administration of mRNA vaccine as the (heterologous) booster to inactivated vaccine may improve the vaccine immunogenicity when compared to vaccination with inactivated vaccines alone, or may even provide more advantage when compared to using inactivated vaccine as the (homologous) booster. Conversely, one may consider receiving an inactivated vaccine as a booster to (the primary series of) mRNA vaccines for presumably less post-vaccination reactions.
For further discussion on the need for COVID-19 vaccine boosters, please visit this page from the World Health Organisation (English only).
科學資訊

有關2019冠狀病毒病(COVID-19)

在2019年底初發的2019冠狀病毒病(COVID-19)及其後的全球大流行,至2020年底時已於全球造成數百萬的死亡和重大的經濟影響。COVID-19由感染SARS-CoV-2冠狀病毒(新冠病毒)所引起,感染後病情嚴重性可以從無症狀,出現常見呼吸道症狀但能很快復原﹐或出現嚴重症狀以致需要住院、導致長期後遺症或死亡。

有關COVID-19疫苗

接種COVID-19疫苗可預防感染新冠病毒或減低出現嚴重疾病的機會,更可通過增加群體免疫力來幫助減少社區傳播。不同COVID-19疫苗種類包括滅活疫苗(如科興、國藥)、mRNA疫苗(如復必泰、莫德納)、病毒載體疫苗(如牛津-阿斯利康疫苗、強生疫苗、俄羅斯衛星五號),這些不同的製造方法會影響不同免疫機制的反應(如抗體免疫、細胞免疫、先天免疫),及影響所需接種頻率。如其他疫苗一樣,接種COVID-19疫苗後可能出現輕微過敏反應(副作用)如輕微發燒、接種部位紅腫或疼痛,或在罕見的情況下出現嚴重過敏反應。
更多有關COVID-19疫苗的資料可瀏覽香港政府2019冠狀病毒病疫苗接種計劃網頁

有關疫苗加強劑

當我們說為現時的新冠疫苗接種計劃提供「疫苗加強劑」時,通常是指為早前已接種兩劑新冠疫苗人士接種第三劑新冠疫苗。可能會促使個人考慮接種第三劑新冠疫苗的一些原因包括:
  1. 在一些較脆弱的群體中如免疫力較弱人士,與其他更健康人士相比,在接種前兩劑新冠疫苗後可能並未能產生足夠強的免疫保護反應
  2. 在任何人士,接種疫苗後的免疫反應可能會隨著時間自然地下降
  3. 一些新冠疫苗對抵抗新出現的新冠病毒株的效用可能較差
初步數據顯示,使用復必泰或科興疫苗作為第三劑同類型疫苗(同源,homologous)或不同類型疫苗(異源,heterologous)接種是安全的,而其他疫苗設計的數據更提出接種第三劑後的反應甚或可能低於接種第一劑後的反應。可以預期,與單獨接種滅活疫苗相比,使用mRNA疫苗作為滅活疫苗(異源)加強劑或可提高疫苗的免疫原性,甚至比使用滅活疫苗作為(同源)加強劑或更有優勢。相反,使用滅活疫苗作為mRNA疫苗加強劑或能降低接種後的反應。
更多有關新冠疫苗加強劑的討論可瀏覽此世界衞生組織網頁(只提供英文版本)
About Us
Our team at the School of Public Health, the University of Hong Kong are experts in infectious disease epidemiology. This study is led by Prof. Benjamin Cowling and Dr. Nancy Leung.
The School of Public Health, LKS Faculty of Medicine of The University of Hong Kong (HKUSPH) has a long and distinguished history in public health education and high impact research. With world leading research in infectious diseases as well as on non-communicable diseases of both local and global importance, we have made significant contributions through its research and advocacy to improve the health of populations and individuals, both locally and globally. The School is a leading research and teaching hub in public health on influenza and other emerging viruses, control of non-communicable and infectious diseases, tobacco control, air pollution, psycho-oncology, behavioural sciences, exercise science, life-course epidemiology, and health economics, health services planning and management. Work done by us has informed international (e.g. the World Health Organization and the Food and Agriculture Organization), national and local public health policies.
The School of Public Health hosts the WHO Collaborating Centre (WHO CC) for Infectious Disease Epidemiology and Control. With a view to protecting the public's health in Hong Kong and across the region, the WHO CC aims to coordinating research on the control and prevention of infectious diseases and providing local and regional education and training in infectious disease epidemiology and control. Members of the WHO CC are involved in the response to COVID-19 and conducted a range of scientific research projects. The team has created a website (click here to visit) to share the latest scientific findings and the implications for evidence-based public health policies on the ongoing COVID-19 pandemic.
關於我們
我們的研究團隊是來自香港大學公共衞生學院的傳染病流行病學專家。本研究由高本恩教授及梁曉灡博士籌辦。
香港大學醫學院公共衞生學院乃頂尖的科研和教學中心,在公共衞生教育及科研方面有多年經驗,成就卓越。我們有關傳染病及非傳染性疾病的研究工作在國際間舉足輕重,對改善本地和全球個人及人口健康有非常重大的貢獻,對教育工作亦不遺餘力。當中包括對傳染病如流行性感冒及其他新發傳染病病毒的教學及研究,亦致力於非傳染性疾病的控制、控煙、空氣污染、心理腫瘤學、行為科學、運動科學、生命歷程流行病學、醫療經濟效益、醫療服務規劃及管理等有關的研究工作。當中不少研究獲本地、國內以至國際組織(如世界衞生組織和聯合國糧食及農業組織)認同,納入其公共衞生政策當中。
港大公共衞生學院同時亦為世衞傳染病流行病學及控制合作中心(世衞合作中心)。以守護香港以至周邊地區公共健康為願景,世衞合作中心旨在協調傳染病防控有關研究,為本地及區內傳染病流行病學及控制提供教育及培訓。世衞合作中心成員現正致力於2019冠狀病毒病(COVID-19)的應對工作,並開展了多項有關學術研究計劃。研究團隊製作了網上平台(按此瀏覽網站),分享與2019冠狀病毒病相關的最新科學研究成果,以及提供實據作為公共衞生政策的基礎。