Merck has resumed shipments of all vaccine products following the shutdown of its West Point, Penn. manufacturing facility in late 2001.

Merck voluntarily stopped production in late August after FDA raised sterility concerns during a routine GMP inspection. The production halt continued while scheduled facility modifications were implemented at the end of September.

Merck says that all of its vaccines are being shipped out weekly, but is not projecting when supply levels will be back to normal.

The West Point facility manufacturing issues are affecting the supply of all Merck vaccines including Varivax (live varicella virus), MMR II (measles, mumps and rubella vaccine live), Pneumovax 23 (polyvalent pneumococcal vaccine), Comvax (haemophilus b/hepatitis B vaccine), Recombivax HB (hepatitis B) and PedvaxHIB (haemophilus b).

The manufacturing issues also affected some of Merck's sterile pharmaceutical products, including Cancidas (caspofungin) and Timoptic XE (timolol) (¹ Also see "HPV Vaccine Accelerated Approval May Affect Safety Data Collection" - Pink Sheet, 10 December, 2001., p. 3).

Supply problems are also anticipated for the prefilled syringe form of Merck's hepatitis A vaccine Vaqta . Merck has initiated recalls in 25 countries for subpotent antigen levels, which it says are unrelated to the problems at the West Point facility.

Production of Merck's chicken pox vaccine Varivax resumed in late October. Merck currently needs 60 days on average to fill Varivax orders, as compared to the Centers for Disease Control & Prevention's "gold standard" of 15 days. CDC has 500,000 doses on backorder.

As of Jan. 14, orders had been shipped only through Nov. 25, representing a six week delay in shipping orders, but that delay has since increased, CDC National Immunization Program Support Branch Program Chief Dean Mason told the National Vaccine Advisory Committee Feb. 5.

As of the week of Feb. 4, orders up to Nov. 29 had been shipped, Mason said. "We're now around eight weeks of delay in varicella vaccine supply."

Varicella supply for November and December averaged 265,000 doses, a 55% decline from the average monthly supply for January through October. CDC estimates the need for varicella vaccine at 500,000 to 583,000 doses per month; Merck had been averaging 600,000 doses before the plant shutdown.

CDC expects the shortage of Varivax will not be resolved until late summer at the earliest.

"The outlook for varicella vaccine may be the most depressing" of the current vaccine shortages in the U.S., Mason said. "It's a rapidly deteriorating supply. It's not improving."

Merck supplied a total of 5.9 mil. Varivax doses in 2001, down from 6.3 mil. in 2000. "There doesn't appear to be a significant drop there, but I think with each year you've had increased demand, so that exacerbates the problem," Mason pointed out.

Merck is telling physicians to keep a registry of all patients that did not receive the vaccine during the shortage and to contact those patients for vaccination with Varivax when it becomes available.

CDC's Advisory Committee on Immunization Practices will discuss potential changes to varicella immunization recommendations during a Feb. 20-21 meeting in Atlanta.

MMR vaccine is also experiencing a supply drop-off, with monthly supply for October and November averaging 586,000 doses, representing a 61% decrease as compared to all other months for 2001, Mason said. CDC estimates annual MMR vaccine need at approximately 13 mil. doses. Total MMR supplied in 2001 was 10.6 mil. doses, down 18% from 2000.

Merck requested 700,000 doses of MMR II from the CDC stockpile. All doses were shipped as of Jan. 21, but some states are receiving only partial shipments of the vaccine, Mason said.

Mason predicted additional shortages for Merck vaccines "across the board," including Pedvax HIB, which currently requires up to 60 days to fill orders. Order fill time will decrease to 15-30 days in March.

Comvax order-fill time is projected to increase during March and April, with supply returning to normal in May or June.

Merck Vaccine Shipments Resume; CDC Varivax Orders On 8-Week Backlog

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