Updated: January 3rd, 2022
Which is the best vaccine available in Hong Kong? We look at both options and score them according to different criteria. All scores are given out of a maximum of 10 for each criterion with a maximum score of 80 overall.
- Effectiveness on Individual Basis
- Population Effectiveness
- Side Effects
- Effectiveness Against Variants
- Generating an Antibody Response
- Cost of Vaccination
- Ease of Manufacture, Storage and Distribution
- Need for Booster Doses
Effectiveness on Individual Basis
We have a large number of studies internationally. Both vaccines are very effective in preventing death and serious disease. We have better evidence for BioNTech in preventing milder disease and transmission. This means on an individual basis both are very effective. BioNTech has consistently been shown to be the most effective both in studies and in large populations.
Population Effectiveness (Reaching Herd Immunity)
We have explained in a previous article that it is highly unlikely any countries will be able to reach Herd Immunity by vaccination alone. In population terms any immunity is good, but if we cannot reach herd immunity just with vaccinations, it is especially important that we vaccinate the old and the vulnerable in order to ensure they have individual protection. In population terms, the more effective a vaccine is in reducing mild disease and transmission, the better for the group. In this regard, BioNTech is a better vaccine.
Serious side effects are very rare with both vaccines. Mild side effects are more common with BioNTech. We have discussed the side effects of Covid vaccines in a previous article, mild side effects are not always a bad thing. Often this is a sign of the development of effective immunity.
Effectiveness Against Variants
Variants reduce the effectiveness of vaccinations. We have better evidence for sustained effectiveness for BioNTech. Against the original virus BioNTech was 95% effective compared to 50.7% for Sinovac. BioNTech drops to 88% against Delta. Recent studies suggest that Sinovac is significantly less effective against Delta and has no neutralizing immunity against Omicron. Booster doses of BioNTech have been shown to be significantly better against variants than Sinovac boosters. We advise all patients in Hong Kong without contraindications to take BioNTech as a booster dose regardless of which vaccine they took in the original series.
Generating an Antibody Response
Both vaccinations produce an effective immune response. We know from recent studies from The University of Hong Kong University that BioNTech produces a 10x greater antibody response than Sinovac. Other studies internationally have now shown waning of antibodies with killed vaccines (such as Sinovac) more quickly.
Cost of Vaccination
BioNTech is a new technology and is currently significantly more expensive. Both vaccines have been made available through Covax although internationally the cost makes Sinovac a significantly more accessible option.
Ease of Manufacture, Storage and Distribution
As a new technology, the manufacture and distribution of BioNTech are significantly more difficult. This contributes to the expense. It must be stored at extremely low temperatures. Recently, we have increasing evidence that it can be stored for longer after being reconstituted. This will make delivery in medical clinics and family health centres easier in the future. Sinovac can be stored in a standard fridge. Manufacture, distribution and storage are easier for killed vaccines such as Sinovac.
Need and Effectiveness of Booster Doses
We have discussed booster doses in another article. Both vaccines available in Hong Kong require booster shots. We now have good evidence from international studies that booster shots do not just restore the immunity which develops after the initial two shots. A booster shot has been shown to significantly improve both antibody response but also T cell and memory cell immunity. In some ways, there is an argument to say that the third shot is not technically a booster. Rather that the Covid vaccines require three shots for optimal immunity. BioNTech has been shown to be the most effective vaccine in boosting immunity regardless of the initial vaccine given.
|Effectiveness on Individual Basis||6||9|
|Effectiveness Against Variants||3||9|
|Generating an Antibody Response||5||9|
|Cost of Vaccination||9||6|
|Ease of Manufacture, Storage and Distribution||9||7|
|Need for Booster Doses||5||9|
Both vaccines are very good at stopping individuals from becoming seriously ill or dying. For individuals both vaccinations are excellent. Sinovac has the advantage of being a more traditional vaccine which is easier to make, cheaper and as such is easier to distribute to larger populations. It also has fewer mild side effects. BioNTech is more expensive, logistically more difficult to distribute and has more mild side effects. However, it is more effective on an individual level in reducing total disease and transmission. In population terms, this makes it a much better vaccine. It is also more effective against variants. From an individual perspective, both vaccines will be very good. From the perspective of the population, we need as many people as possible, especially those who are older or more vulnerable, to be vaccinated with the most effective vaccine to give us the greatest chance of reaching Herd Immunity with minimal damage from infections. In this regard, considering Hong Kong has excellent logistics and a free vaccination program, BioNTech is the better vaccine and we should be encouraging as many people as possible to be vaccinated with this vaccination.