Vaccine types and schedules

Vaccines

Vaccines are biological products administered in the form of injections, nasal sprays, or oral drops that stimulate our immune system by exposing it to controlled amounts of weakened or dead microbes or their components. The immune system reacts by producing protective antibodies. Vaccines provide active immunity. Most vaccines, including inactivated vaccines and the live nasal spray influenza vaccine, are refrigerated. However, some vaccines, like the chickenpox (varicella) vaccine, VARIVAX, and Zostavax shingles vaccine, are stored frozen. Pfizer COVID-19 vaccine is stored, prior to thawing, in an ultracold freezer between -80 to -60 degrees Celsius. If a frozen vaccine needs to be prepared, it should be slowly defrosted in a refrigerator. Before administering a vaccine, its lot number, expiry date, and manufacturer are recorded, and a vaccine information statement or VIS is given to the patient.

Depending on the type of vaccine components and the resulting immune response, vaccines can be classified as follows:

Vaccine adverse effects include fever, local erythema and swelling after DTaP booster doses, allergic reactions to neomycin in MMR, IPV and chickenpox vaccines. Influenza vaccine is contraindicated in serious egg allergies. Thimerosal is a mercury containing preservative used in some vaccines and can be potentially toxic to the developing brain of infants.

CDC immunization schedule for under 18 years of age: The recommended immunization schedule for children includes the Hepatitis B vaccine administered at birth, followed by boosters at 1 and 6 months of age, and a third dose at 18 months. Rotavirus vaccines are given in 2 doses between 2-4 months. Diphtheria, tetanus and acellular pertussis or DTaP, pneumococcal conjugate vaccine PCV 15 or 20, and inactivated polio vaccine are given as 4 separate doses typically in 2,4,6 months, followed by 9-15 months of age. An additional dose of DTaP and IPV is given between 4-6 years of age. At ages 10-12, a Tdap vaccine is administered. Haemophilus influenzae type b (Hib) vaccine is given in 3 or 4 doses, the first two doses in months 2 and 4, and the third or fourth doses between 9-15 months. Influenza vaccines are administered annually in the flu season. The first dose of MMR and Varicella vaccines is given between 12-15 months, and the second dose is between 4-6 years of age. Meningococcal vaccines are given at age 11-12 years and 16 years of age.

CDC recommended vaccines in adults: Certain vaccinations are recommended by CDC to prevent diseases like herpes zoster, pneumococcal pneumonia, severe flu, and COVID-19 pneumonia in susceptible adults. Shingles or herpes zoster vaccination, called RZV (recombinant zoster vaccine) or Shingrix, is given as 2 doses 2-6 months apart after the age of 50 years. HPV vaccine is administered in 2-3 doses depending on the initial age at immunization, starting at age 9 years.