The Advisory Committee on Immunization Practices (ACIP) of the Centers for Disease Control and Prevention (CDC) met June 24-25 in Atlanta. This article reviews the key discussions and decisions pertinent to clinicians.
Use of Meningococcal Serogroup B Vaccines
Two vaccines have been licensed for the prevention of invasive disease caused by serotype B Neisseria meningitidis in persons 10 through 25 years of age. The vaccines are MenB-FHbp (Trumenba, Pfizer), licensed in October, 2014 and given in a three-dose series, and MenB-4C (Bexsero, Novartis) licensed in January, 2015 and given in a two-dose series.
MenB vaccines are comprised of serogroup B proteins, thus the vaccines differ significantly from the capsular polysaccharide vaccines that provide protection against meningococcal serotypes A, C, W and Y.
At the ACIP meeting in February 2015, the ACIP voted to recommend MenB vaccine to prevent disease in people >10 years old with an increased risk for meningococcal disease.
This includes people with persistent complement component deficiencies, people with anatomic or functional asplenia, microbiologists routinely exposed to isolates of N. meningitidis, and people identified as at increased risk because of a serogroup B meningococcal disease outbreak. An interim protocol has been developed by CDC for use of MenB vaccine in an outbreak in an organizational setting, which has been used on college campuses experiencing an outbreak of serogroup B meningococcal disease.
At the June meeting, ACIP took up the issue of immunization of otherwise healthy adolescents and young adults. The United States is now experiencing an all-time low of reported meningococcal cases, including a significant decrease in cases caused by serotype B meningococcus, resulting in an overall low disease burden. However, the morbidity of meningococcal sepsis and meningitis remain high with mortality rates of 7-12%.
Approximately 55-65 cases of serogroup B meningococcal disease occur in adolescents and young adults each year. The majority of these cases occur in 16-24 year olds and 40-70% of the serogroup B cases in 18-23 year olds occur in college students. Although outbreaks of serogroup B meningococcus have been identified on college campuses, the overall U.S. incidence in same-age college and non-college students is similar.
ACIP determined that there is not enough evidence for universal immunization with MenB vaccines, in part because of the low incidence and the need for additional experience with the MenB vaccines; specifically, more data are needed on overall effectiveness, effectiveness against non-related meningococcal B strains, duration of protection, effect on carriage and safety.
ACIP voted for a Category B recommendation for administration of a MenB vaccine series to adolescents and young adults 16 through 23 years of age to provide short-term protection against most strains of serogroup B meningococcal disease.
The preferred age for MenB vaccination is 16 through 18 years of age. A Category B recommendation indicates that the consideration for use of the vaccine is based on individual clinical decision making. Either vaccine can be used, but the same vaccine product should be used to complete the series. The vaccines may be administered concomitantly with other vaccines indicated for age.
Pneumococcal Vaccine Recommendations
ACIP voted to harmonize recommendations for the sequential use of pneumococcal vaccines for the prevention of invasive pneumococcal disease in people >65 years old.
In August 2014, the ACIP added 13-valent pneumococcal conjugate vaccine (PCV13) to the recommendations for vaccination of >65 year olds.
PCV13 is recommended at age 65 years, followed in >1 year by 23-valent pneumococcal polysaccharide vaccine (PPSV23). If a person > 65 years old, has received PPSV23, PCV13 should be given >1 year later. Insufficient data are available to determine the interval required between doses of these two vaccines to obtain maximum protection for a person naïve to pneumococcal vaccines or to those people who received an initial dose of PCV13 or PPSV23. However, in adults, some data suggest a longer interval results in a better seroresponse rate and less reactogenicity.
Therefore, >1 year is now recommended between pneumococcal vaccine doses in people >65 years old, regardless of which vaccine was given first. No change was recommended for sequential use of these vaccines in children or for persons >19 years old with underlying conditions which increase the risk for invasive pneumococcal disease.
ACIP was also presented data from the 2014-15 influenza season.
Influenza A H3N2 was the predominant strain earlier this year, with a small peak of influenza B near the end of the season. More than 80% of the H3N2 isolates tested showed antigenic drift from the H3N2 strain in the vaccine. Overall effectiveness of the 2014-15 influenza vaccine against the mutated H3N2 type this season, as evaluated in the United States Influenza Vaccine Effectiveness Network, was only 13%.
Vaccine effectiveness against influenza B was 66-67% among children and adolescents with no significant difference between Live Attenuated Influenza Vaccine and Inactivated Influenza Vaccine. No new safety concerns were detected through surveillance.
Officials with Sanofi Pasteur presented data on their quadrivalent formulation of intradermal influenza vaccine, which is expected to be licensed for the 2015-16 season. An expanded age indication for Flublok, 18 and older, is also expected.
New H3N2 and B Yamagata lineage strains have been selected for the 2015-16 influenza vaccine formulation. A simplified algorithm for determining the number of doses needed for children 6 months through 8 years of age based on receipt of influenza vaccines in previous influenza seasons was approved for the 2015-16 season. If a child in this age group has received 2 or more doses of trivalent or quadrivalent influenza vaccine, the child will need one dose of influenza vaccine, if not, or it is not known how many doses the child has received, two doses are needed, given >4 weeks apart.
Human Papillomavirus Vaccine
ACIP reviewed guidance prepared for providers and the public in the form of a question and answer period to address common questions being raised during the transition from the four-valent HPV vaccine (4vHPV) to the nine-valent HPV vaccine (9vHPV) and approved the placement of the guidance on the ACIP website.
9vHPV vaccine adds five additional oncogenic types to the 4vHPV vaccine. In the United States, these five types are responsible for 14% of HPV-related cancers in women and 4% of HPV-related cancers in men.
9vHPV vaccine is now available and most insurers have included the vaccine in their panels. People who have begun the HPV vaccination series with 4vHPV vaccine can complete the remaining doses of the three-dose series with 9vHPV; no additional doses are recommended. ACIP will discuss the issues related to giving additional doses of 9vHPV to women who have completed the three dose series with quadirvalent vaccine at a future meeting.
Other ACIP actions
ACIP approved the update of the final sections of the General Recommendations for Immunization document which is updated approximately every five years. ACIP also approved updated recommendations for use of the currently available smallpox vaccine, ACAM2000, for laboratory and healthcare workers at risk for exposure to orthopoxviruses.
Smallpox vaccine is recommended for laboratory workers who directly handle cultures or animals contaminated or infected with replication-competent vaccinia strains or other orthopoxviruses that infect humans.