Immunizations and Vaccines: An Overview of Recent Updates

In his presentation, “Immunization Update: Recent Recommendations from the Advisory Committee on Immunization Practices,” Wednesday morning at the 2010 AAFP Scientific Assembly, Douglas Campos-Outcalt, MD, clinical professor and associate head of the Department of Family and Community Medicine, University of Arizona College of Medicine, gave a top-level update on the upcoming influenza season and the evolving child, adolescent, and adult immunization schedules, and reviewed several precautions regarding the timing of several vaccines and their appropriateness for specific patient populations.

Peak influenza activity is from December to March, and typically peaks in February, said Campos-Outcalt. Hospitalization rates due to influenza vary by age group; last year the highest rate was for young children (0-4 years), with a rate of about 16-22 hospitalizations per 100,000 patients for other age groups. The death rate was highest among the 50-64 age group (1.75 deaths per 100,000 patients). There were two vaccines last year (H1N1 and seasonal). Vaccination rates are improving, but still not where we want them to be, said Campos-Outcalt. Less than 50% of children and adults got both vaccines. For the 2010-2011 flu season, it is recommended that all people age 6 months and older receive an annual flu vaccination. The 2010-2011 H1N1 is the same strain as last year; there is also a new strain, the H3N2. Trivalent inactivated and live attenuated influenza virus (LAIV) vaccines are available, but the LAIV is only for healthy patients 2-49 years of age. Children under the age of 9 should receive two doses of seasonal flu vaccine if they are receiving the vaccine for first time this year, if they only received one dose of seasonal vaccine last year, or if they received no H1N1 vaccination last year. Campos-Outcalt cautioned that the product Afluria should not be used in children under the age of 9, except in children age 5-8 who are at high risk for influenza complications and if no other seasonal TIV is available. Current recommendations are that all health care workers should be immunized.

Contrasting the childhood vaccine schedule from 25 years ago, which had essentially three vaccines, Campos-Outcalt noted that the current vaccination guidelines call for “many more antigens and a more complicated dosing schedule.” He quickly highlighted several key considerations:

Rotavirus

Contraindications for the rotavirus vaccines include a history of serious allergic reaction to a previous dose of the vaccine and a history of severe hypersensitivity to any component of the vaccine. Last year, the FDA recommended suspending administration of Rotarix until the agency learned more about the components of an extraneous virus that was detected in the vaccine (porcine circovirus 1). The advisory has been rescinded after studies found that it was not harmful and not known to cause illness in humans.

MMRV

MMRV vaccines are associated with increased risk of febrile seizures in 12-23 month-old patients who receive one dose of MMRV vs. MMR and varicella vaccines during same office visit. There is limited availability of the MMRV vaccine due to manufacturing constraints.

Polio vaccine

The last dose of polio vaccine should be after the age of 4 years and six months from prior dose; minimal intervals should be used in the first six months of life only if the patient is travelling overseas.

Meningococcal disease

Routine use of the MCV4-D and MenACWY-CRM meningococcal vaccines is recommended for patients ages 11-12 years. For children age 2-10 years who are at increased risk, vaccinate with MCV4 (revaccinate at three-year intervals if already received MPSV4). Persons age 2-55 years who remain at high risk for meningococcal disease should get a booster of MCV4 or MPSV4 with MCV4 five years after vaccination (after three years if vaccinated at age 2-6 years).

Pneumococcal disease

The 13-valent Pneumococcal conjugate vaccine (PCV13) is approved for use in children age 6 weeks to 5 years (should be administered before the 6th birthday). PCV13 should be administered in a four-dose series at age 2, 4, 6, and 12-15 months. PCV13 recommended schedules for children younger than 24 months depends on age at examination and vaccination history with prior pneumococcal vaccine. Transition from PCV7 to PCV13 depends on number of doses previously received. For children over the age of 24 months, a healthy child who is unvaccinated or had incomplete dosing can receive one dose of PCV13. Children at age 6-18 years with high-risk conditions (sickle cell disease, HIV, cochlear implant, etc) are also candidates. Children older than two years with underlying medical conditions should also receive PPSV23.

Vaccine safety

Vaccine safety monitoring measures include the vaccine adverse event reporting system, which is a post-marketing surveillance system with mandatory reporting by manufacturers. There is also an active system, the Active Surveillance Vaccine Safety Datalink, which is a collaboration between the CDC and eight geographically determined HMOs.

HPV vaccines

For HPV-associated disease there are two vaccines: Gardasil and Cervarix (which offers no protection against genital lesions). ACIP recommends routine vaccination of females age 11-12 years, with catch-up doses for age 13-26, and has no preference for either vaccine. These vaccines are not recommended for use in pregnancy. Initiation should be delayed until after completion of pregnancy; if initial dose has already been administered after conception, remaining doses should be halted until the end of the pregnancy. If administered during pregnancy, there is no recommended intervention.

Tdap and pertussis

A single dose of Tdap (combined Tetanus, Diphtheria and Pertussis vaccines) should replace the next dose of Td vaccine in older adults. A single dose of Tdap should be administered to adults who have close contact with infants younger than 12 months of age. Women of childbearing age should receive Tdap preconception or postpartum.

Postherpetic neuralgia and shingles

There is a 32% lifetime risk of shingles among the adult population; 10-18% will develop postherpetic neuralgia. The rates of shingles increase with age. Herpes zoster vaccine is recommended routinely in patients age 60 years and older, and is most effective at ages 60-80 years. It is contraindicated in immune-compromised patients.

Hepatitis A post-exposure prophylaxis

Hepatitis A vaccination is recommended for all previously unvaccinated persons who anticipate close contact with a child adopted from overseas.