Merck (known as MSD outside the United States and Canada) manufactures more than a dozen FDA-approved vaccines covering diseases from childhood infections to cancer-causing viruses. Its portfolio spans routine pediatric immunizations, adult pneumococcal vaccines, and specialized products like an Ebola vaccine. Here’s a breakdown of every vaccine Merck currently produces and what each one protects against.
HPV: Gardasil 9
Gardasil 9 is one of Merck’s most widely recognized vaccines. It protects against nine strains of human papillomavirus (HPV types 6, 11, 16, 18, 31, 33, 45, 52, and 58), which together account for the vast majority of HPV-related cervical cancers, genital warts, and several other cancers affecting the throat, anus, and genitals.
Children who start the series between ages 9 and 14 need only two doses, spaced 6 to 12 months apart. Anyone who begins at age 15 or older, or who has a weakened immune system, receives three doses over about six months.
Measles, Mumps, Rubella, and Varicella
Merck makes the core childhood vaccines that protect against measles, mumps, rubella, and chickenpox. These come in three products:
- M-M-R II covers measles, mumps, and rubella using live, weakened viruses. It has been a cornerstone of the U.S. childhood immunization schedule for decades.
- Varivax protects against varicella (chickenpox) using a live, weakened form of the varicella-zoster virus.
- ProQuad combines all four into a single shot, reducing the total number of injections a child needs. It contains the same virus strains found in M-M-R II and Varivax.
Pneumococcal Vaccines
Merck produces three vaccines targeting Streptococcus pneumoniae, the bacterium behind pneumonia, bloodstream infections, and meningitis. Each covers a different range of bacterial subtypes (serotypes):
- Pneumovax 23 is a longstanding polysaccharide vaccine that covers 23 serotypes. It has been used primarily in older adults and people with certain chronic conditions.
- Vaxneuvance is a newer conjugate vaccine covering 15 serotypes. Conjugate vaccines generally produce a stronger, longer-lasting immune response than polysaccharide vaccines.
- Capvaxive is Merck’s newest pneumococcal vaccine, approved by the FDA in June 2024. It covers 21 serotypes and is indicated for adults 18 and older. It protects against both invasive pneumococcal disease and pneumococcal pneumonia.
Hepatitis A and Hepatitis B
Merck makes a vaccine for each type of viral hepatitis commonly prevented by immunization:
- Vaqta protects against hepatitis A, a liver infection typically spread through contaminated food or water. It is recommended for all children at age one and for adults traveling to high-risk areas.
- Recombivax HB protects against hepatitis B, a virus that spreads through blood and body fluids and can cause chronic liver disease. Notably, Recombivax HB was the first recombinant vaccine ever produced, meaning it was made using genetically engineered proteins rather than killed or weakened virus.
Rotavirus: RotaTeq
RotaTeq is an oral vaccine (not a shot) that protects infants against rotavirus, a leading cause of severe diarrhea and dehydration in young children worldwide. It covers five rotavirus types: G1, G2, G3, G4, and G9.
The series consists of three liquid doses given by mouth. The first dose is given between 6 and 12 weeks of age, with follow-up doses spaced 4 to 10 weeks apart. The final dose must be given before 32 weeks of age.
Hib: PedvaxHIB
PedvaxHIB protects against Haemophilus influenzae type b, a bacterium that can cause meningitis, pneumonia, and other serious infections in young children. Before Hib vaccines became routine, this was one of the most common causes of bacterial meningitis in kids under five.
Ebola: Ervebo
Ervebo is an FDA-approved vaccine for the prevention of Ebola virus disease (specifically the Zaire species, which has caused the largest and deadliest outbreaks). It is approved for people 12 months of age and older. The vaccine requires ultra-cold storage at temperatures between negative 60°C and negative 80°C during shipping, though it can be kept in a standard refrigerator for up to 14 days once thawed. This makes distribution challenging in the remote settings where Ebola outbreaks tend to occur, but it remains a critical tool for outbreak response.
RSV: Clesrovimab (Enflonsia)
Merck’s newest addition to its portfolio is clesrovimab, marketed as Enflonsia. This is a monoclonal antibody product for respiratory syncytial virus (RSV), the virus that causes bronchiolitis and pneumonia in infants and young children. Rather than training the immune system to make its own antibodies, monoclonal antibody products deliver ready-made protective antibodies directly.
Manufacturing Scale
Producing vaccines at this scale requires massive infrastructure. Merck opened a dedicated $1 billion, 225,000-square-foot vaccine manufacturing facility at its Durham, North Carolina, site to expand production capacity. The company operates additional manufacturing sites to supply its vaccines both domestically and globally, where it sells under the name MSD.