Some localized responses to the vaccines, such as experiencing stiffness or mild swelling at the site of injection can be quite painful and make it difficult to move the arm. While massaging the area or a soothing rub may seem to be very helpful and relieve any inflammation, experts advise against doing so with vaccines. Swiftly rubbing at the particular point of injection, too, may be bad.
One of the primary reasons as to why this is advised is because of the manner in which the vaccines are injected, i.e. through an intramuscular route. With intramuscular vaccines (most of the COVID-19 vaccine shots are delivered through this mean right now), rubbing, pinching or massaging the injection site may interfere with the effectiveness of the vaccine. While it may seem to relieve and quench the soreness that follows inoculation, massaging at the point may seldom cause the drug to back up through the subcutaneous tissue present in the deepest layer of your skin, so, as a safety measure, massages or hard rubs are best avoided for the time being. Some also suggest that the vaccines are very delicately pressed into the arm, so such an action could lead to undesirable effects as well.
Vaccinators also suggest that rubbing or massaging should be avoided immediately after, or hours after vaccination, when it is expected that the vaccine drug reaches its peak levels and thus avoid counter absorption.