Vaccines Not As Effective In Obese People – Using A Longer Needle Helps
A vaccine is most effective when given in the intramuscular position, meaning the vaccine substance and molecules enter the muscle tissue where the immune fighting antibodies can be activated. If the vaccine is simply injected into the subcutaneous fat then it is probably less effective at generating immunity. We have long known that vaccines were less effective in obese individuals, probably as a result of this fact. Now recent studies indicate that vaccines are more effective when a longer needle is used, presumably because the vaccine can enter directly into the muscle tissue and not be wasted in the subcutaneous fat.
It is striking to me that virtually every facet of health and disease is adversely affected by obesity, even preventive efforts such as vaccinations. In this most recent study analyzing the effect of Hepatitis B vaccines, the Baylor College of Medicine researches compared the antibody levels with short needles compared to long needles. The antibody numbers when short needles were used were about half of that when a longer needle is used. The authors note that there already exists a CDC recommendation to use longer needles (usually 1.5-inch long) in obese individuals.