CDC’s Advisory Committee on Immunization Practice (ACIP) met in Atlanta on October 21, 2015, to discuss vaccine recommendations. Complete minutes of the meeting will be published on the CDC National Immunization Program website. Following is a summary of the committee's discussions.
Surveillance of influenza worldwide has demonstrated a wide variety of circulating virus types, but ACIP noted that the U.S. vaccine should offer protection against most of these circulating viruses. Specifically, ACIP discussed how the circulating influenza A virus subtype H3N2 (A/H3N2) has been identified as slightly antigenically different from the vaccine strain in the current U.S. vaccine, but this difference is not considered significant.
The influenza vaccine supply is adequate, with 171 to 179 million doses available this season (147.8 million doses last year) and 109.4 million doses distributed as of October 9, 2015. Few delays in shipment were reported, with MedImmune and Sanofi Pasteur distributing partial shipments of vaccine supply to fairly distribute doses.
In addition, a cost-effective analysis presented by Sanofi Pasteur showed that high-dose influenza vaccine (Fluzone High-Dose) was more cost effective than Fluzone regular dose. Sanofi demonstrated a societal cost increase of $128 per vaccine with the regular-dose vaccine when hospitalization and other medical costs are considered, even though the high-dose vaccine costs more.
Novartis also presented data on an adjuvanted influenza vaccine that has been used in Europe and Canada (approximately 30 countries) for the last 17 years, with approximately 76 million doses distributed. The vaccine contains a MF59 adjuvant, which enhances the immune response using squalene and surfactants. Its mechanism of action involves the recruitment of immune cells and activation of T- and B-cells. Thirty-nine studies have demonstrated noninferior immunological responses as well as higher antibody titers compared with the nonadjuvanted vaccine. Specifically, the vaccine results in a higher immune response to drifted strains and a safety profile similar to the nonadjuvanted vaccine. The Vaccines and Related Biological Products Advisory Committee recently voted for its use in patients 65 years and older.
Many challenges are known with the current meningococcal B policy statement approved in June 2015. The policy statement reads, “A serogroup B meningococcal (MenB) vaccine series may be administered 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 (Category B).”
ACIP noted that the actual number of meningococcal B cases that could be prevented by giving the vaccine are unknown and the duration of protection is limited. The primary unknowns include the following: strain coverage has not been clinically proven, effectiveness data are not currently available, and the impact on carriage and on circulating strains are unknown. Safety and immunological studies are ongoing, and Pfizer will present additional data in February 2016.
The CDC Immunization Safety Office has been following safety reports on use of the meningococcal B vaccination. Data from the Vaccine Adverse Event Reporting System revealed few reports (86), with no safety signals. In addition, an assessment of data from the Vaccine Safety Datalink (VSD) revealed that not enough doses have been administered in this population to do an evaluation. More information will be presented at the February or June ACIP meeting.
An outbreak of meningococcal C in Chicago among men who have sex with men was presented, including a description of the investigation and vaccination clinics. Many challenges were seen in reaching the population, in communication, and in vaccine delivery. The cost of the investigation and vaccination process was estimated to be approximately $70,000.
At its February 2015 meeting, ACIP recommended that the 9-valent HPV vaccine (Gardasil 9—Merck), licensed in December 2014, replace the 4-valent HPV vaccine. ACIP revisited the recommendation at its June 2015 meeting and decided not to recommend revaccination if the 4-valent HPV series has already been completed. In addition, CDC has published a guidance statement on its website for use of the 9-valent HPV vaccine.
Data on the uptake of HPV vaccine remains low, and reasons for low uptake were presented.
The proposed Child and Adolescent Immunization schedule was also presented. Once approved by ACIP, the American Academy of Pediatrics, the American Academy of Family Physicians, and the American Congress of Obstetricians and Gynecologists, the schedule will be released in January or February 2016.
Table and footnote changes include the following:
The adult schedule was also revised to reflect changes in the meningococcal B recommendations. These include separating the MenACWY and B into separate rows, adding high-risk and category B recommendations, noting the doses are different in the MenB products, and noting that there are no routine recommendations for travelers and no revaccination recommendations.
Other changes included clarifying pneumococcal recommendations, such as intervals between pneumococcal polysaccharide vaccine and pneumococcal conjugate vaccine (PCV13 or Prevnar 13) doses, adding the 9-valent HPV vaccine, clarifying Hib dosing (i.e., one dose over a lifetime, except for patients with posthematopoietic stem cell transplantation), describing available HPV vaccines, and many other footnote changes.
The inactivated JE-VC vaccine (Ixiaro), the only JE-VC vaccine available in the United States, is now distributed by Valneva (Novartis had U.S. distribution agreement). Data presented on the use of Ixiaro in patients 65 years and older showed a lower seroconversion rate and lower geometric mean titer in this patient population; however, no long-term studies have been conducted to understand the significance of these findings. The committee noted that a booster dose may be needed.
In addition, data on a study looking at an accelerated dosing schedule (0 and 7 days vs. 0 and 28 days) and its use with rabies vaccine was presented. Short-term data on use of the accelerated rate was positive, and use with rabies vaccine was safe and immunogenic. The company plans to submit data to FDA, and the ACIP working group will discuss in future meetings.
A new hexavalent pediatric vaccine DTaP-IPV-Hib-HepB (Merck and Sanofi Pasteur), currently under review by FDA, is expected to be approved later this year.
Currently no cholera vaccine is licensed in the United States. A new vaccine (CVD 103-HgR) is under review by FDA. ACIP will review the data, immunogenicity, and efficacy in time for an anticipated approved in late 2016.
ACIP’s next meeting is scheduled for February 24–25, 2016.