I composed a post about this topic on my Facebook in 2021, but since my links to FB posts don't seem to go through on this site, I won't bother trying to link to it.
The Orthodox Church is not against the principle of traditional vaccination, per se. The Orthodox Churches of Russia and Greece promoted the use of the smallpox vaccine in the 1800s. You can read about it in the writings of saints like Innocent of Alaska and Nicholas of Japan, for example, as well as Prot. No. 2997 of the Church of Greece in 1864.
Saint Innocent (Benjaminov), Metropolitan of Moscow
Letters. Volume I. 1828-1855
https://azbyka.ru/otechnik/Innokentij_M ... sma-tom-1/
Saint Innocent (Benjaminov), Metropolitan of Moscow
Creations of Innocent Metropolitan of Moscow. Book two
https://azbyka.ru/otechnik/Innokentij_M ... vtoraja/14
Saint Innocent (Benjaminov), Metropolitan of Moscow
Creations of Innokenty, Metropolitan of Moscow. Book 3
https://azbyka.ru/otechnik/Innokentij_M ... a-tretja/2
Equal to the Apostles Nicholas of Japan (Kasatkin)
Diaries. Volume III
https://azbyka.ru/otechnik/Nikolaj_Japo ... -tom-iii/3
Like eish said, the prospect of receiving vaccines of more recent provenance (or the COVID pseudo-vaccines, which aren't vaccines at all, but poison) which are derived, developed, or tested by means of the use of cells taken from aborted babies, is unconscionable, and must absolutely be rejected by Christians.
Since the same godless and lawless authorities which tried to coerce and seduce the public into taking the sinful C-19 shots have shown themselves to be sinister, cunning, and completely untrustworthy, I don't see why any Christian would be interested in taking any of their other purported "vaccines" either, including the annual "flu shot".
The Orthodox Word #87
149 Martyrology of the Communist Yoke: Eldress Agatha of Belo-Russia
ELDRESS AGATHA OF BELO-RUSSIA
Commemorated on February 5
(excerpt)
Among her numerous visitors were many family people who had children of school age. She advised parents that their children who attended school should not enter into the groups of the “Octoberites," "Pioneers,” "Young Communists," and so forth. She likewise advised that their children should not take vaccinations which were periodically given to school children. This was justified by the fact that at one time children died by being infected by the vaccinations.
Concerning the Soviet church she said, "This is not a true church. It has signed a contract to serve antichrist. Do not go to it. Do not receive any Mysteries from its servants. Do not participate in prayer with them.