How were the vaccines tested?

The clinical trials for COVID-19 vaccines have involved tens of thousands of volunteers of different ages, races, and ethnicities. Clinical trials for vaccines compare outcomes (such as how many people get sick) between people who are vaccinated and people who are not. Because COVID-19 continues to be widespread, the vaccine clinical trials have been conducted more quickly than if the disease were less common. Results from these trials have shown that COVID-19 vaccines are effective. They have also shown no serious safety concerns after more than 8 weeks following vaccination. This is an important milestone, as it is unusual for adverse effects caused by vaccines to appear after this amount of time.

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1. Is the COVID-19 vaccine safe?
2. What are the ingredients in the COVID-19 vaccine?
3. How do COVID-19 vaccines work?
4. Which COVID-19 vaccine should I get?
5. How long does it take to be fully protected after receiving the vaccine?
6. Will I have a positive COVID-19 test after getting the vaccine?
7. Do I still need to wear a mask after getting the COVID-19 vaccine?
8. If I’ve been vaccinated and was exposed to someone who has COVID-19, do I need to quarantine?
9. Can the COVID-19 vaccine help me even if I've already been affected by COVID-19?
10. Can I get my flu shot at the same times as my COVID shot?
11. Can women who are pregnant get the COVID-19 vaccine?
12. Why was I told to wait a month after getting the vaccine before getting a mammogram?
13. How do COVID-19 vaccines protect the community?
14. Does the vaccine have any side effects?
15. What is V-safe?
16. How much does the vaccine cost?
17. Are the vaccines FDA approved?
18. How were the vaccines tested?