Potential supply issues for varicella-containing vaccines

Late last month, the CDC's MMWR included a "Notice to Readers" titled "Supply of Vaccines Containing Varicella-Zoster Virus." What are those vaccines? Varivax (against chickenpox), Zostavax (against shingles), and Proquad (a combination of MMR and chickenpox). All are manufactured by Merck, and no other U.S. companies manufacture vaccines providing protection against VZV.

There's no shortage to report, only news from Merck that the yield produced from early stages of the vaccine manufacturing process are less than expected (the reasons for which are not yet known). In the meantime, the plan is to prioritize production of the chickenpox and shingles vaccines, creating the potential for a limited supply of the combination ProQuad by late 2007. Again, not a major issue, as children can receive the same protection by receiving MMR and Varivax separately.

However, this announcement does remind us of the potential fragility of the U.S. vaccine supply. In addition to varicella-containing vaccines, those against measles, mumps, rubella, HPV, and rotavirus, among others, are all produced by a single manufacturer in the U.S. While the economic reasons behind this single-supplier market have been discussed by many, minor hiccups such as this announcement raise the attention of those who worry that the system is not sufficiently insulated against the risk, however small, of major production problems affecting a recommended vaccine.

Shingles vaccine recommended for adults 60+

We'd be remiss not to mention the biggest development out of this week's ACIP meeting, namely, the recommendation that all adults age 60 and over receive a single dose of Merck's new shingles vaccine, Zostavax. Here's the CDC press release, the Merck press release, and an AP story (courtesy of the Washington Post).

Also useful is this site assembled by the NIP with numerous resources about the painful condition formally known as herpes zoster and the new vaccine against it. Zostavax was licensed by the FDA in May and is the latest in a series of new vaccines introduced by Merck during the past year, though it's safe to say that this news hasn't received a hundredth of the attention that went to Gardasil in June.

ACIP: June minutes and October agenda

The folks at the Immunization Action Coalition pointed out that the full minutes from the June 2006 meeting of the CDC Advisory Committee on Immunization Practices are now available here. The 96-page PDF is the next best thing to attending the meeting yourself, as it provides comprehensive coverage of everything that took place. In June, of course, the major news was the recommendation vote for Merck's HPV vaccine, Gardasil. For those interested in the data that informed the ACIP's recommendation, the report is invaluable.

Also on the ACIP website is a draft agenda for the group's next meeting, scheduled for October 25-26. The most notable item is a scheduled vote on a recommendation for Merck's shingles vaccine, Zostavax, for use in adults.