CDC Advisory Committee Recommends Changes to MMRV Vaccine Schedule, Sparking Industry Debate

The pharmaceutical industry is grappling with the implications of recent recommendations by the Centers for Disease Control and Prevention's (CDC) Advisory Committee on Immunization Practices (ACIP) regarding the measles, mumps, rubella, and varicella (MMRV) vaccine schedule. The committee's decision has ignited discussions about vaccine safety, efficacy, and the role of healthcare providers in immunization choices.

ACIP Recommends Age Restriction for MMRV Combination Vaccine

Last week, the ACIP voted to recommend a significant change to the MMRV vaccine schedule, advising that the four-way combination shot be restricted to children aged four and older. For children under four, the committee now recommends administering the measles, mumps, and rubella (MMR) vaccine separately from the varicella (chickenpox) vaccine.

This recommendation marks a departure from the previous guidelines, which allowed for two doses of the combo MMRV vaccine—one at 12-15 months and another between ages 4 and 6—or the option to administer MMR and chickenpox vaccines separately, preferably during the same visit.

The rationale behind this change stems from concerns over a rare risk associated with the MMRV vaccine: febrile seizures. According to CDC data, the use of the combination shot resulted in approximately one extra febrile seizure for every 2,300-2,600 doses administered, compared to separate administrations of MMR and varicella vaccines.

Merck's ProQuad at the Center of the Debate

Merck's ProQuad, the only four-way MMRV vaccine authorized in the United States, has been thrust into the spotlight following the ACIP's recommendation. Approved in September 2005 for children aged 12 months through 12 years, ProQuad combined two of Merck's previously approved vaccines, M-M-R II and Varivax, into a single administration.

In response to the ACIP's decision, Merck expressed concern over the removal of choice for healthcare providers. The company stated, "The recent ACIP vote regarding the MMRV vaccine and the discussion around hepatitis B vaccination occurred in the absence of new scientific data—in contrast to the historical practice of new data driving any discussions for changes to the recommendations pertaining to immunization schedules."

Merck defended its vaccine lineup in a letter sent to the ACIP committee prior to the hearing and urged the committee to "reinstate liaison organizations and clinicians with frontline experience to its work groups," emphasizing the importance of transparency and scientific integrity in the decision-making process.

Financial Impact and Industry Implications

While the ACIP's recommendation is unlikely to have a significant financial impact on Merck, it raises questions about the future of combination vaccines and the balance between convenience and safety in pediatric immunizations.

Merck reports combined sales for ProQuad, M-M-R-II, and Varivax, which totaled $609 million in recent financial disclosures. The company maintains that healthcare providers can still use the triple MMR vaccine in conjunction with Varivax as an alternative to ProQuad.

The pharmaceutical industry is closely watching these developments, as they may influence future vaccine development strategies and regulatory approaches. GSK, another major player in the vaccine market, recently entered the U.S. MMR vaccine space with its Priorix vaccine in 2022, although its four-way MMRV vaccine, Priorix Tetra, is not yet approved in the United States.

As the debate continues, the pharmaceutical industry, healthcare providers, and public health officials will need to navigate the complex landscape of vaccine recommendations, balancing scientific evidence, public health goals, and the diverse needs of patients and healthcare systems.