Is Sinovac's vaccine so lousy?

Well, I am a staunch believer in the saying, the devil lies in the details, and have conducted my own research on Sinovac's vaccine efficacy.

I will reveal what I've found out for the newly published low efficacy rate (50.4%).

https://fortune.com/2021/01/13/sinovac-vaccine-efficacy-rate-drop/

It turns out that Sinovac has more stringent and comprehensive trials conducted in Brazil compared to other vaccine manufacturers.

Sinovac's efficacy included many mild and asymptomatic subjects but other vaccine manufacturers didn't count these subjects as infected cases in their trials which explained the much higher efficacy rates.  Furthermore, Sinovac's trials included a lot of high-risk subjects (healthcare workers) compared to the US & UK trials.

However, Sinovac and Astrazeneca have a 100% efficacy rate against severe covid which is the most important because this will mean we won't end up in the hospitals.

Astrazeneca's vaccine has only 62% efficacy when injected with 2 full doses but has 100% efficacy against severe covid.

https://www.abc.net.au/news/2021-01-13/government-coronavirus-vaccine-rollout-astrazeneca-efficacy/13053302

No matter what, it is still best to be vaccinated because this will protect us from getting a severe covid.  However, the immunity might only be temporary (5 months) as stipulated in the latest UK research.

https://www.reuters.com/article/health-coronavirus-immunity/covid-19-infection-gives-some-immunity-for-at-least-5-months-uk-study-finds-idUSL8N2JO4MM

What will I choose then?

Well, I will choose the upcoming J&J's vaccine because it only requires 1 injection and this means that I will only need to suffer the side effects once instead of twice for other vaccines.

https://www.cnbc.com/2021/01/13/covid-vaccine-johnson-johnson-one-shot-safe-generates-immune-response.html