Why do We Need to Be Concern about Some Vaccine Effectiveness Studies (Part 2) ?

In Part 1,  we found that those studies done using real World Data are actually not measuring the vaccine effectiveness but a combination of vaccine and the other Covid-19 control measures.   These other control measures are shutdowns & isolation,  mask-wearing, etc.    This Part 2 will suggest a way where we can use to monitor how effective are these combined Covid-19 control measures.  We can term this "the effectiveness of the Covid-19 control measures". 

How?

By comparing the attack rates of Covid-19 against those data obtained from the vaccine efficacy trial results or an acceptable level or limit.

What data?

From the vaccine efficacy trial results for the 3 vaccines,  namely,  Pfizer, Moderna & Johnson & Johnson,   we can obtain the following data:

a)  The average attack rate for the vaccine group was 0.24% and for the placebo group,  1.25%.  The standard efficacy formula is as follows

b)  Using the same standard formula,  we can plot out a chart showing the attack rates of the vaccine group against vaccine efficacy as shown in the following chart

Chart 1:  Attack rates of Vaccinated Group at various Vaccine Efficacies

Comparing the Attack Rates

Using the attack rates at various vaccine efficacies,  we can draw up a chart showing how effective is the Covid control measures as compared to the vaccine efficacies shown in Chart 1.  This is Chart 2 which plotted  "the Attack Rates by Vaccination Status".  This chart uses Singapore MOH's Real World Data

Doubleclick picture for latest updates

Interpretation?

1. Chart 2 illustrated that Singapore has good control over Covid-19 infection at present. It uses a combination of the following measures:

a) Vaccination: To date, 80% of the 5.9 million residents have received full-dose and 85% of them have at least 1-dose;

 b) Mask wearing & social safety distancing for all residents are compulsory for all indoor as well as outdoor activities;

 c) All social, religious gatherings and sporting events are controlled by having a cap on the maximum number of attendees as well as other controls;

         d) Business events and other events are curtailed;

e) Other measures are as shown here

2. The above control measures in Singapore are showing to have a Covid attack rate even better than the 95% vaccine efficacy;

3. The remaining 15% of the unvaccinated residents in Singapore have exercised good control measures to prevent themselves from getting infected. As many as 60,000 Singaporeans have already been infected before Singapore rolled out its vaccination program in Feb 2021. They would have the natural immunization without acquiring vaccines. Many could have been infected without noticing it because they were asymptomatic. The unvaccinated residents in Singapore have better attack rates at the present moment.

4. We can use this method to monitor how effective are our control measures and what would happen if we relax any of the control measures.

Conclusion

1. We could monitor the effectiveness of the control measures implemented in various countries by comparing the Covid-19 attack rates of the residents against those of the Vaccine Trial Tests;

2. The real World Data cannot be used to measure the vaccine effectiveness unless one can discount the effect due to all the biases and other Covid-19 control measures that will affect vaccine effectiveness calculation;

3. The standard formula cannot be used when more people in the population have been vaccinated.

The charts and table as shown will be updated daily and presented on this webpage.