Some people who are against vaccinations see healing as a spiritual thing, and think that vaccinations, being unnatural, are not spiritual. I also believe that healing is spiritual, but I also believe that vaccinations are spiritual.
But how does spiritual healing work? How does the Divine Spirit impact on a physical body? Answer, it uses things in the world as its agent. As Abdu’l-Baha says in the quote below: “The spirit operateth through the instrumentality of the hand.” He is answering someone who asked him how the Divine Spirit can provide someone with material means to meet their needs. He explains that the Divine Spirit provides material means by using something as its instrument, and that could be anything.
He gives an example. God has ordained that water is the means for quenching thirst. A person who refuses material means is like a thirsty person who refuses water because it is material. But although water is material, it is still the spiritual solution to thirst, because it is the agent chosen by the Divine Spirit for thirsty people.
This agency can come in any number of forms, and vaccination is one of them. The Divine Spirit works through vaccinations to heal people of Covid-19. It doesn’t matter if the vaccination did not originate in nature, or that it is not a natural substance, or that it is a material substance. It is still a spiritual solution to a physical illness.
“Thou hast asked about material means and prayer. Prayer is like the spirit and material means are like the human hand. The spirit operateth through the instrumentality of the hand. Although the one true God is the All-Provider, it is the earth which is the means to supply sustenance. “The heaven hath sustenance for you” [Qur’an 51:22] but when sustenance is decreed, it becomes available, whatever the means may be. When man refuseth to use material means, he is like a thirsty one who seeketh to quench his thirst through means other than water or other liquids. The Almighty Lord is the provider of water, and its maker, and hath decreed that it be used to quench man’s thirst, but its use is dependent upon His Will. If it should not be in conformity with His Will, man is afflicted with a thirst which the oceans cannot quench.” — Abdu’l-Baha, from The Importance of Prayer, Meditation and the Devotional Attitude in Compilation of Compliations, volume 2, pp231-2, no 1742.