In almost all age groups, if you are not vaccinated, the excess mortality rate brought by COVID-19 is relatively high.
(excess death: refers to the excess amount compared with the average mortality rate of the same age group)
This point can be found that even young people have excessive deaths caused by the new crown:

North American Actuary Association mortality rate report
Therefore, all age groups need vaccination to protect themselves. This minimizes the risk of death.
However, we can find that the same vaccination has different degrees of benefit for different age groups.
From the data from Hong Kong, it can be found that after routinely receiving 3 shots of vaccine , the mortality rate of people <60>
- <40>
0-49 years old: The mortality rate after 3 shots is 0.01%, which is just one in ten thousand.
0-59 years old: the mortality rate after 3 shots is 0.02%, which is just two out of ten thousand.
However, this is not the case for the elderly.
- 60-69 years old: the mortality rate after 3 shots is 0.06%, which is just 6 in 10,000.
- 70-79 years old: the mortality rate after 3 injections is 0.23%, that is, 2.3 per thousand
- ≥80 years old: The mortality rate after 3 injections is 1.71%


data summarized by Hong Kong on December 7, 2022
We can find that with age, even the mortality rate after 3 injections is still steadily increasing. And the rise is suddenly higher at the age of ≥80. It is 10 times or even more than 50 times that of previous age groups.
In fact, more than 95% of new crown deaths in Hong Kong have an age of ≥60 years old, and the median death age is 86 years old. This shows that the deaths are actually concentrated at ≥80 years old.

Data summarized by Hong Kong on December 7, 2022
What if 4 injections are inoculated?
1, <50>2, aged 50-59, the mortality rate after 4 shots is 0.01%, which is just one in ten thousand.
Look at the elderly population
1, 60-69 years old: the mortality rate after 4 injections is 0.02%, which is just two out of ten thousand.
2, 70-79 years old: the mortality rate after 4 injections is 0.10%, that is, one in a thousand
3, ≥80 years old: the mortality rate after 4 injections is 1.06%
We can find that the mortality rate in people aged <70 is very low.
If 0.02% is the limit.
We can find that 3-pill vaccination can push people under 60 years old to this limit; while 4-pill vaccination can push people under 70 years old to this limit.
However, even if you get 4 shots, the mortality rate for people aged ≥70 is still ≥0.1%, while the ≥80 is even more 1.06%.

Hong Kong data summarized on December 7, 2022
Not only that, among people aged ≥70, Sinovac vaccine is significantly worse than Fubitai.
If 3 shots are given, the mortality rate of Sinovac vaccinated patients is twice that of Fubitai!
When you see 4 vaccinations, the mortality rate of Sinovac vaccine is still twice that of Fubitai. At the same time, it should be noted that for aged 70-79 years old, the mortality rate of 3 injections is 4 times that of 4 injections. However, the decline in 4 vaccination for ≥80 years old was only about 50%. This means that if people aged ≥80, if they use the "older generation new crown vaccine " to receive 4 shots, their benefits will further decrease. Hong Kong data summarized on December 7, 2022, you can see the comparison between Sinovac vaccine and Fubitai Although Fubitai is better than Sinovac vaccine, 5.7% of the 4 shots of people aged ≥80 years old are still 5.7% after 4 shots of people who are ≥80 years old. This is still a high level.
1, 70-79 years old: 0.29% (Science and Technology) VS (Fubitai) 0.15%
2, ≥80 years old: 1.94% (Science and Technology) VS (Fubitai) 0.97%
1, 70-79 years old: 0.07% (Science and Technology) VS (Fobitai) 0.04%
2, ≥80 years old: 1.27% (Science and Technology) VS (Fobitai) 0.57% 
According to the data of most deceased in Hong Kong, if you want to further reduce the number of deaths, even the first generation of Fubitai is not ideal. The inactivated vaccine , represented by Sinovac vaccine, is even more unsatisfied.
So, in the face of the COVID-19 outbreak like a tsunami, we need to increase the number of vaccinations (this is the main one), and we also need better vaccines, namely the second-generation COVID-19 vaccine (this is the icing on the cake)