"Should yoga practitioners believe in science and be vaccinated, or not?"
Life is science. Human's body mechanism is science. Human's behavior is science. Hormones, secretions, bodily organs and systems, cells, atoms, neurons, muscular and bone structures and etc, are science. Selflessness and Impermanence is science. How everything exist, change, and ceased existing, is science. The nature's law of cause and effect is science. Yoga of silence is science beyond names and forms.
One is fearless towards making the appropriate decision and the consequences of one's decision, uninfluenced by one's family and friends and community's different opinions about the vaccines. There's no perfection in any decision and action. There are pros and cons in any actions. The fearless beings perform actions based on what is most beneficial for the world to move forward, without attachment, identification, judgment, or expectation.
The teachings of yoga doesn't discriminate any kind of names and forms, not to say, anyone's decision towards getting vaccinated, or not, especially in a prolonged pandemic situation. The difference between yoga practitioner and non-yoga practitioner is whether one inquires the truth of everything without being influenced by any particular worldly thinking and belief that are under the influence of ignorance and egoism to judge everything, or not.