PRESS RELEASE: Merck Announces Voluntary Recall of Certain Lots of PEDVAXHIB and COMVAX

Merck Announces Voluntary Recall of Certain Lots of PEDVAXHIB and COMVAX

WHITEHOUSE STATION, N.J., Dec. 12, 2007 - Merck & Co., Inc. announced today that the Company has initiated a voluntary recall of 11 lots of its Haemophilus influenzae type B vaccine, PEDVAXHIB [Haemophilus b Conjugate Vaccine (Meningococcal Protein Conjugate)], and two lots of its combination Haemophilus influenzae type B/ hepatitis B vaccine, COMVAX [Haemophilus b Conjugate (Meningococcal Protein Conjugate)].  The recall is specific to these 13 lots and does not affect any other vaccines manufactured by Merck.  The affected doses of PEDVAXHIB and COMVAX were distributed starting in April 2007.

Merck is conducting this recall because it can not assure sterility of these specific vaccine lots.  The potential contamination of these specific lots was identified as part of the Company's standard evaluation of its manufacturing processes.  Sterility tests of the vaccine lots that are the subject of this recall have not found any contamination in the vaccine.

The potential for contamination of any individual vaccine is low, and, if present, the level of contamination would be low.  However, because the Company cannot assure the sterility of these specific lots of vaccine, it is conducting this recall.

Merck is working closely with the U.S. Food and Drug Administration (FDA) and the U.S. Centers for Disease Control and Prevention (CDC) to inform affected healthcare providers of this recall.  We are also in the process of communicating with public health authorities and healthcare providers in the U.S. and in other countries where these lots were distributed, as appropriate.

"We are taking this action because we are committed to ensuring the quality of our vaccines," said Mark Feinberg, M.D., Ph.D., vice president, Medical and Policy Affairs, Merck Vaccines and Infectious Diseases.  "We know that our vaccines can play an important role in the nation's public health system, and we are committed to resolving this issue as quickly as possible to ensure that our vaccines are readily available."

Physicians are advised not to administer any vaccine from the vaccine lots being recalled.  Individuals who received vaccine from these lots should complete their immunization series with a Haemophilus b conjugate-containing vaccine not affected by this recall, but do not need to be revaccinated to replace a dose they received from a recalled lot.  The efficacy of the vaccine was not affected.

Select safety and additional information about PEDVAXHIB
PEDVAXHIB is indicated for routine vaccination against invasive disease caused by Haemophilius influenzae type b in infants and children two to 71 months of age.  PEDVAXHIB should not be used in infants younger than six weeks of age.

PEDVAXHIB is contraindicated in patients with hypersensitivity to any component of the vaccine or the diluent; persons who develop symptoms suggestive of hypersensitivity after an injection should not receive further injections of the vaccine.

As with any vaccine, the use of PEDVAXHIB may not result in a protective antibody response in all vaccinees; PEDVAXHIB may not induce protective antibody levels immediately following vaccination.

The most frequently reported (>1 percent) adverse reactions, without regard to causality, were fever (>101F), irritability, sleepiness, injection-site pain/soreness, injection-site erythema (<2.5 cm diameter), injection-site swelling/induration (<2.5 cm diameter), unusual high-pitched crying, prolonged crying (>4 hours), diarrhea, vomiting, crying, pain, otitis media, rash, and upper respiratory infection.

Select safety and additional information about COMVAX
COMVAX [Haemophilus b Conjugate (Meningococcal Protein Conjugate) and Hepatitis B (Recombinant) Vaccine] is indicated for vaccination against invasive disease caused by Haemophilus influenzae type b and against infection caused by all known subtypes of hepatitis B virus in infants six weeks to 15 months of age born to HBsAg-negative mothers.

COMVAX [Haemophilus b Conjugate (Meningococcal Protein Conjugate) and Hepatitis B (Recombinant) Vaccine] is contraindicated in patients with hypersensitivity to yeast or any component of the vaccine.  Patients who develop symptoms suggestive of hypersensitivity after an injection should not receive further injections of the vaccine.  In clinical trials, the most common nonserious adverse experiences observed in ≥1 percent of children receiving COMVAX [Haemophilus b Conjugate (Meningococcal Protein Conjugate) and Hepatitis B (Recombinant) Vaccine] included injection-site reactions, somnolence, irritability, crying, and fever (≥101F); for a listing of adverse reactions, please see the Prescribing Information.

As with other vaccines, COMVAX [Haemophilus b Conjugate (Meningococcal Protein Conjugate) and Hepatitis B (Recombinant) Vaccine] may not induce protective antibody levels immediately following vaccination and may not result in a protective antibody response in all individuals given the vaccine.

About Merck
Merck & Co., Inc. is a global research-driven pharmaceutical company dedicated to putting patients first.  Established in 1891, Merck currently discovers, develops, manufactures and markets vaccines and medicines to address unmet medical needs.  The Company devotes extensive efforts to increase access to medicines through far-reaching programs that not only donate Merck medicines but help deliver them to the people who need them.  Merck also publishes unbiased health information as a not-for-profit service.  For more information, visit www.merck.com [1].

Forward-Looking Statement
This press release contains "forward-looking statements" as that term is defined in the Private Securities Litigation Reform Act of 1995.  These statements are based on management's current expectations and involve risks and uncertainties, which may cause results to differ materially from those set forth in the statements.  The forward-looking statements may include statements regarding product development, product potential or financial performance.  No forward-looking statement can be guaranteed and actual results may differ materially from those projected.  Merck undertakes no obligation to publicly update any forward-looking statement, whether as a result of new information, future events, or otherwise.  Forward-looking statements in this press release should be evaluated together with the many uncertainties that affect Merck's business, particularly those mentioned in the risk factors and cautionary statements in Item 1A of Merck's Form 10-K for the year ended Dec. 31, 2006, and in its periodic reports on Form 10-Q and Form 8-K, which the Company incorporates by reference.