COVID-19 Vaccines in Hong Kong: Which One to Choose?

There is currently an explosion of information, comments and opinions on COVID-19 on the Internet and social media. We believe that on serious topics in general, and on public health matters in particular, it is essential that you rely on facts and credible, expert information. Our mission at Alea is to bring you the best possible information and advice, so you can make the best choices for you and your family.

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Have you decided to protect yourself and your community by getting a COVID-19 vaccine?

If the answer is yes, you currently have two vaccine options in Hong Kong.

To help you decide, we bring you unique insights from Healthy Matters’ Expert Advisory Board Member, Joseph Blais, Registered Pharmacist in Hong Kong.

In this guide you will find an exclusive comparison table of the most important vaccine information. If you need more details, there are additional resources at the end of this article. We hope that you find this guide useful.

For a full Chinese guide about COVID-19 Vaccine Options in Hong Kong, please click here.

中文版的香港新冠疫苗之選擇及全面比較請按此。

Which vaccine should I choose?

This is a common question that healthcare professionals face when comparing all types of treatments, not only for COVID-19 vaccines. When comparing treatment choices for a particular disease or health condition, it is best to first evaluate the key characteristics of any drug or vaccine. Individuals choosing COVID-19 vaccines should consider these five characteristics in the following order:

1. Efficacy: How well does the vaccine work in the strict conditions of a randomized clinical trial?
2. Safety: What are the known vaccine side effects and how frequently do they occur in both the vaccine and placebo groups? What is the frequency of severe or rare side effects outside of the clinical trial setting?
3. Adherence: How simple is it to adhere to the recommended vaccine dosing schedule?
4. Cost: Fortunately, in Hong Kong there is no personal financial cost to receiving the COVID-19 vaccine. However, you should also consider the time required to book online (or at your doctor’s office), the time needed to receive the vaccine, and time to travel to your nearest community vaccination center.
5. Availability, personal preferences and values: Do you prefer getting the vaccine in your doctor’s office or at a community vaccination center? Do you want to read the published clinical trial results in a scientific journal? The Hong Kong Government has signed purchasing contracts for three vaccines. Two vaccines (Comirnaty and CoronaVac) have been authorized for emergency use and are currently available in Hong Kong.

*The shipment of the third vaccine from Oxford/AstraZeneca is suspended for the year, as the government announced amid concerns over rare cases of blood clots after the shot.

All information regarding the vaccines is regularly reviewed and updated accordingly.

Comparison: COVID-19 vaccine options in detail

	Comirnaty	CoronaVac
Other names	COVID-19 mRNA Vaccine (BNT162b2)	COVID-19 Vaccine (Vero Cell) Inactivated
Manufacturer	BioNTech, Germany Fosun Pharma has partnered and obtained rights to market the BioNTech vaccine in China	SinoVac Life Science, China
Type of vaccine	mRNA vaccine embedded in lipid nanoparticles	Inactivated whole virion vaccine with aluminum hydroxide as the adjuvant
Safety	Real-world experience anaphylaxis: 4.7 cases/million vaccine doses given in US	No serious AE related to the product have been reported as of 3 February 2021
- Pain at injection site	Vaccine group: 65-80% Control group: 5-15%	Vaccine group: ~60% Control group: ~35%
- Fatigue	Vaccine group: 35-60% Control group: 15-35%	Vaccine group: ~15% Control group: ~15%
- Headache	Vaccine group: 25-50% Control group: 15-35%	Vaccine group: ~35% Control group: ~35%
- Fever	Vaccine group: 10-15% Control group: 0-1%	Vaccine group: <1% Control group: <1%
- Serious AE related to product	Vaccine group: <1% (4 cases) Control group: 0	Vaccine group: 0 Control group: 0
Adherence	Two dose vaccine (21 days apart)	Two dose vaccine (28 days apart is recommended in Hong Kong, but 14 days apart was studied in Brazil)
Cost in Hong Kong	None	None. The vaccine is subsidized for patients who receive from doctors. Private doctors will be subsided $80 for each dose and they are not allowed to charge patients for a service fee (or $120 if both doses are given at the same clinic).

* Adverse events (AE) following immunization include any untoward medical occurrence (for example a symptom, disease or abnormal lab test) which follows immunization and which does not necessarily have a causal relationship with the use of the vaccine.

^ In blinded trials, researchers have to unmask/unblind patients in order to identify whether the patient belongs to the vaccine or control group. The masked patient has not yet been unblinded by the researchers.

Comparison: Large clinical trial data

	Comirnaty	CoronaVac
Participants	People >16 years of age (43,448 received injections)	People >18 years of age who are healthcare professionals working in close contact with patients with possible or confirmed COVID-19 (13,396 received injections)
Intervention	BNT162b2 vaccine 21 days apart	CoronaVac 3 μg/0.5 mL (equivalent to 600 SU per dose) 14 days apart
Comparator	Saline placebo injection 21 days apart	Placebo injection (contains aluminum hydroxide) 14 days apart
Main outcome	Confirmed symptomatic COVID-19 at least 7 days after the second dose	Confirmed symptomatic COVID-19 at least 14 days after the second dose
Setting	76% of participants were from the United States. Sites were also in Argentina, Brazil, South Africa, Germany, and Turkey.	Brazil

Comparison: Vaccine efficacy

	Comirnaty	CoronaVac
In the overall study against confirmed COVID-19	95.0% (95% CI: 90.3-97.6)	50.7% (95% CI: 35.7-62.2)
- Disease definition	The presence of at least one symptom (fever, new or increased cough, new or increased shortness of breath, chills, new or increased muscle pain, new loss of taste or smell, sore throat, diarrhoea, or vomiting), combined with a respiratory specimen obtained during the symptomatic period or within 4 days before or after it that was positive for SARS-CoV-2 by nucleic acid testing.	At least one of the following symptoms for two days or more (fever or chills, cough, shortness of breath or difficulty in breathing, fatigue, muscle or body pain, headache, loss of smell or new taste, sore throat, nasal congestion or runny nose, nausea or vomiting, diarrhea) and positive results for SARS-CoV-2 by nucleic acid testing.
- Efficacy based on symptoms reported	Starting 7 days after the second dose	Starting 14 days after the second dose
Efficacy against severe COVID-19	66.4% (95% CI: (-124.7-96.3) 1 case in vaccine group 3 cases in the placebo group	100.0%% (95% CI: 56.4-100.0) 0 cases in vaccine group 10 cases in the placebo group
- Disease definition	Confirmed COVID-19 with one of the following additional features: clinical signs at rest that are indicative of severe systemic illness; respiratory failure; evidence of shock; significant acute renal, hepatic, or neurologic dysfunction; admission to an intensive care unit; or death.	Confirmed COVID-19 with one of the following additional features: clinical signs at rest that are indicative of severe systemic illness; respiratory failure; evidence of shock; significant acute renal, hepatic, or neurologic dysfunction; admission to an intensive care unit; or death.
- Efficacy based on symptoms reported	Starting 14 days after the second dose	Starting 14 days after the second dose
Efficacy against COVID-19 patient requiring...	N/A	Medical treatment 83.7% (95% CI: 58.0-93.7) 5 cases in the vaccine group 30 cases in the placebo group
- Disease definition	N/A	Confirmed COVID-19 with WHO severity level of 3 and above (level three is mild ambulatory disease requiring medical assistance).
- Efficacy based on symptoms reported	N/A	Starting 14 days after the second dose

Abbreviations: CI, confidence interval; NE, not evaluable; WHO, World Health Organization.

Availability, preferences, values to consider

Comirnaty (Fosun-BioNTech, aka Pfizer-BioNTech in rest of the world)

• Available at community vaccination centers.
• If you value getting a vaccine from a Chinese or European company, you'll be able to do both since Fosun Pharma (based in China) and BioNTech (based in Germany) will share the profits of this vaccine sold in China.
• Included a large proportion of adults 65 years and older (21.4% [8613 participants]) in Phase 3 study.
• Does not contain: eggs, preservatives or latex.
• Approved in developed markets (e.g. US, Canada, UK, Singapore, EU) and by the WHO.

CoronaVac (SinoVac)

• Available in medical clinics (private and government general outpatient clinics) and some community vaccination centers
• Clinical trial results have been posted but not yet peer-reviewed/published.
• Limited inclusion of adults >60 years old (only 5.1%, or 632 participants in Brazil study). Although the small Phase 1/2 study from China suggests good immune response in adults >60.
• Active virus particles are grown in African green monkey kidney cells (Vero Cell), inactivated, then adsorbed by aluminum hydroxide.
• Does not contain: preservatives.
• Approved for emergency use by the WHO on June 1, 2021 but not yet approved in a major developed market (i.e. USA, Canada, Europe, or Japan).

Vaxzevria (AstraZeneca)

• Not yet approved for emergency use in Hong Kong.
• Viral vector is produced in genetically modified human embryonic kidney cells (labeled as containing genetically modified organisms).
• Does not contain: preservatives.
• Approved for emergency use in developed markets (e.g., UK, Canada) and by the WHO.

Note: the Hong Kong government suspended the shipments of the AstraZeneca vaccine for the year amid concerns over a rare complication associated with its vaccination. The Oxford-AstraZeneca vaccine will not be available in Hong Kong in 2021.

Professional opinion: Which vaccine is the best?

First, it is important to acknowledge that both available options (Comirnaty from BioNTech and CoronaVac from SinoVac) are good vaccines. Since there are no differences in cost and adherence (both are two dose vaccines), we will focus on comparing efficacy, safety, and availability.

Although difficult to directly compare because of differences in outcome definitions and study settings, Comirnaty appears to be highly effective against both symptomatic COVID-19 (this includes mild forms of the disease) and severe COVID-19. CoronaVac is also highly effective against severe COVID-19, arguably the more important outcome. However, some studies of CoronaVac suggest it may be less effective for mild symptomatic cases of COVID-19.

At the individual level, both of these vaccines would be expected to be highly effective. If you are very concerned about getting even a mild case of COVID-19, then I would recommend Comirnaty given its higher efficacy as compared with CoronaVac. At this point in time, I would also generally recommend Comirnaty for adults aged > 60 years since there is very limited data on this population in the CoronaVac studies, and Comirnaty is effective in older adults.

When we indirectly compare the most common side effects, it appears that they occur more frequently with Comirnaty. The common side effects for both vaccines were generally mild, and usually resolved after 1-2 days. The frequency of a potential side effect should be considered if you need to physically use your arms or can’t afford to take 1-2 days of rest at home. So for younger people who are very busy working or looking after others, CoronaVac may be preferred to minimize taking time-off immediately after receiving the vaccine.

Lastly, in part because it can be stored in a refrigerator, you have more options to obtain CoronaVac. If you can't schedule an appointment at a community vaccination center that has Comirnaty, then it would be a great idea to obtain CoronaVac at a government or private clinic.

A point of clarification: the Pfizer/BioNTech vaccine

You'll often hear people discuss the Pfizer/BioNTech vaccine. In China and Hong Kong, Fosun Pharma has partnered with BioNTech to sell the vaccine, whereas Pfizer has these rights outside of China. It is fundamentally the same BioNTech vaccine, just that in China they have partnered with Fosun Pharma.

Sources and Additional Information

Comirnaty (Fosun Pharma/BioNTech)

Interim clinical trial results

1. Polack FP, Thomas SJ, Kitchin N, Absalon J, Gurtman A, Lockhart S, et al. Safety and Efficacy of the BNT162b2 mRNA Covid-19 Vaccine. New England Journal of Medicine. 2020;383(27):2603- 15. Available here

Rate of anaphylaxis in the US with mRNA vaccines

2. Shimabukuro TT, Cole M, Su JR. Reports of Anaphylaxis After Receipt of mRNA COVID-19 Vaccines in the US—December 14, 2020-January 18, 2021. JAMA. 2021. Available here

US Centers for Disease Control Vaccine Information

3. Available here

Hong Kong Food and Health Bureau

4. Report on Evaluation of Safety, Efficacy and Quality of Comirnaty COVID-19 mRNA Vaccine (BNT162b2) Concentrate for Dispersion for Injection. Available here

CoronaVac (SinoVac)

Phase 3 clinical trial results from Brazilian study (not yet peer-reviewed)

5. Palacios R, Batista AP, Albuquerque CSN, et al. Efficacy and Safety of a COVID-19 Inactivated Vaccine in Healthcare Professionals in Brazil: The PROFISCOV Study. Preprint available from: SSRN. 11 April 2021. Available here.

Published Phase 1/2 Studies from China

6. Zhang Y, Zeng G, Pan H, Li C, Hu Y, Chu K, et al. Safety, tolerability, and immunogenicity of an inactivated SARS-CoV-2 vaccine in healthy adults aged 18–59 years: a randomized, double blind, placebo-controlled, phase 1/2 clinical trial. The Lancet Infectious Diseases. 2021;21(2):181- 92: https://www.thelancet.com/journals/laninf/article/PIIS1473-3099(20)30843-4/fulltext

7. Wu Z, Hu Y, Xu M, Chen Z, Yang W, Jiang Z, et al. Safety, tolerability, and immunogenicity of an inactivated SARS-CoV-2 vaccine (CoronaVac) in healthy adults aged 60 years and older: a randomized, double-blind, placebo-controlled, phase 1/2 clinical trial. The Lancet Infectious Diseases: https://www.thelancet.com/journals/laninf/article/PIIS1473-3099(20)30987-7/fulltext

Hong Kong Food and Health Bureau (has summary study results in Chinese)

8. Report on Evaluation of Safety, Efficacy and Quality of CoronaVac COVID-19 Vaccine (Vero Cell) Inactivated. Available here

Oxford/AstraZeneca Vaccine

Interim Phase 3 clinical trial results

9. Voysey M, Clemens SAC, Madhi SA, Weckx LY, Folegatti PM, Aley PK, et al. Safety and efficacy of the ChAdOx1 nCoV-19 vaccine (AZD1222) against SARS-CoV-2: an interim analysis of four randomized controlled trials in Brazil, South Africa, and the UK. The Lancet. 2021;397(10269):99-111. Available here

Information for Healthcare Professionals on COVID-19 Vaccine AstraZeneca, UK Government

10. Available here

Preliminary Report of Phase 1/2 Safety Data

11. Folegatti PM, Ewer KJ, Aley PK, et al. Safety and immunogenicity of the ChAdOx1 nCoV-19 vaccine against SARS-CoV-2: a preliminary report of a phase 1/2, single-blind, randomized controlled trial. The Lancet 2020; 396(10249): 467-78. Available here

Risk of blood clots following vaccination 12. Available here

Hong Kong Government

13. Authorisation of COVID-19 Vaccines under the Prevention and Control of Disease (Use of Vaccines) Regulation and Summary Data on Approved Products. Available here

14. Consensus Interim Recommendations on the Use of COVID-19 Vaccines in Hong Kong (January 7, 2021). Available here

Other medical resources

JAMA Covid-19 Vaccine Comparison

15. Creech CB, Walker SC, Samuels RJ. SARS-CoV-2 Vaccines. JAMA. 2021. Available here

WHO Emergency Use Listing Status for Covid-19 Vaccines

16. Available here

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--- Joseph Blais is a Registered Pharmacist in Hong Kong and PhD candidate in pharmacoepidemiology at the University of Hong Kong. ---