Actually, the WTS backed off the restriction of having tentanus shots in 1990 using the argument that the mother and chlld exchange certain blood components, and since god created women, it must be okay.
Others have felt (the WTS actually) that a serum (antitoxin), such as immune globulin, containing only a tiny fraction of a donor’s blood plasma and used to bolster their defense against disease, is not the same as a life-sustaining blood transfusion. So their consciences may not forbid them to take immune globulin or similar fractions.* They may conclude that for them the decision will rest primarily on whether they are willing to accept any health risks involved in an injection made from others’ blood.
It is significant that the blood system of a pregnant woman is separate from that of the fetus in her womb; their blood types are often different. The mother does not pass her blood into the fetus. Formed elements (cells) from the mother’s blood do not cross the placental barrier into the fetus’ blood, nor does the plasma as such. In fact, if by some injury the mother’s and the fetus’ blood mingle, health problems can later develop (Rh or ABO incompatibility). However, some substances from the plasma cross into the fetus’ circulation. Do plasma proteins, such as immune globulin and albumin? Yes, some do.
A pregnant woman has an active mechanism by which some immune globulin moves from the mother’s blood to the fetus’. Because this natural movement of antibodies into the fetus occurs in all pregnancies, babies are born with a degree of normal protective immunity to certain infections.
It is similar with albumin, which doctors may prescribe as a treatment for shock or certain other conditions.* Researchers have proved that albumin from the plasma is also transported, though less efficiently, across the placenta from a mother into her fetus.
That some protein fractions from the plasma do move naturally into the blood system of another individual (the fetus) may be another consideration when a Christian is deciding whether he will accept immune globulin, albumin, or similar injections of plasma fractions. One person may feel that he in good conscience can; another may conclude that he cannot. Each must resolve the matter personally before God.
Past comments by WTS condemning vaccinationshttp://www.religioustolerance.org/witness6.htm