Type of Vaccines

Here are the four basic types of vaccines. 

Live-attenuated vaccines: use a weakened (or attenuated) version of the germ that causes a specific disease. One or two doses of the vaccines can provide strong, life-long protection. However, these types of vaccines can be problematic for those with compromised immune systems or organ transplants. Examples of live-attenuated vaccines include measles/mumps/rubella (MMR), rotavirus, smallpox, chickenpox and yellow fever.

Inactivated vaccines: use a killed version of the germ that causes a specific disease. Because these vaccines are not as strong as live-attenuated vaccines, you’ll probably need several doses (or boosters) of the vaccine to maintain protection. But on the upside, the potential of having a reaction to one of these vaccines is relatively low. Examples of inactivate vaccines include hepatitis A, influenza (flu), polio and rabies.

Subunit, recombinant, polysaccharide and conjugate vaccines: use particular sections of a germ that causes a specific disease, such as its protein or the casing around it. These vaccines are both strong and safe for everyone but require boosters. Examples of these vaccines include influenza type b (Hib), hepatitis B, human papillomavirus (HPV), whooping cough (DTaP), pneumococcal disease, meningococcal disease, shingles. Scientists are studying subunit vaccines for coronavirus such as SARS, MERS and COVID-19.

Toxoid vaccines: use a toxin produced by the germ that causes a specific disease. This causes an immunity to the toxin, but not the actual germ. Boosters are commonly needed for these vaccines. Examples of toxoid vaccines include diphtheria and tetanus.