Watchtower teachings on medical topics have varied wildly over the years. Vaccines are one of these areas. Initially Watchtower ruled that Jehovah's Witnesses could not vacinate, but several decades later vaccinations were allowed.
For a discussion on Watchtower changes regarding medical procedures see Medical.
Golden Age 1921 October 12 p.17
"Vaccination never prevented anything and never will, and is the most barbarous practice...We are in the last days; and the devil is slowly losing his hold, making a strenuous effort meanwhile to do all the damage he can, and to his credit can such evils be placed...Use your rights as American citizens to forever abolish the devilish practice of vaccinations."
Golden Age 1931 February 4 p.293
"Vaccination is a direct violation of the everlasting covenant that God made with Noah after the flood."
Golden Age 1939 May 31 p.5
Golden Age 1932 March 30 p.409
Watchtower 1952 December 15 p.764
"The matter of vaccination is one for the individual that has to face it to decide for himself....And our Society cannot afford to be drawn into the affair legally or take the responsibility for the way the case turns out."
Awake! 1993 August 8 p.25
"Previous articles in this journal and its companion, The Watchtower, have presented a consistent position: It would be up to the Bible-trained conscience of the individual Christian as to whether he would accept [vaccinations] for himself and his family."
Announcement 2020 Dec 3
"Several COVID-19 vaccines may soon be approved and become available. Some have asked if these vaccines contain blood or blood fractions. We have confirmed that the COVID-19 vaccine manufactured by Pfizer and BioNTech (COVID-19 mRNA Vaccine BNT162b2) does not contain blood or blood fractions. As details become avail- able regarding other vaccines, additional information will be provided. Medical care is a matter for personal decision. We do not attempt to make choices for others."