A hexavalent vaccine is a single combination shot that protects against six diseases: diphtheria, tetanus, pertussis (whooping cough), polio, hepatitis B, and Haemophilus influenzae type b (Hib). It’s designed for infants and young children, replacing what would otherwise be multiple separate injections during the first years of life.
The Six Diseases It Covers
Each of the six components targets a different infection, all of which can be serious or fatal in young children:
- Diphtheria causes a thick coating in the throat that can block breathing. The vaccine uses an inactivated form of the toxin the bacteria produces.
- Tetanus triggers severe muscle spasms and lockjaw. Like diphtheria, it uses an inactivated toxin.
- Pertussis (whooping cough) causes intense, prolonged coughing fits that are especially dangerous for newborns. The vaccine contains purified proteins from the pertussis bacteria rather than whole killed bacteria, which is why it’s called “acellular” pertussis.
- Polio can cause permanent paralysis. The hexavalent vaccine uses inactivated (killed) poliovirus covering all three strains.
- Hepatitis B is a liver infection that can become chronic and lead to liver damage or cancer. The vaccine uses a surface protein from the virus, grown in yeast cells.
- Hib (Haemophilus influenzae type b) causes meningitis, pneumonia, and other invasive infections in young children. The vaccine works by linking a sugar from the bacteria’s outer coating to a carrier protein, which helps an infant’s immune system recognize and respond to it.
Available Brands
Three hexavalent vaccines are produced by major manufacturers. Infanrix Hexa, made by GSK and first licensed in Europe in 2000, is widely used globally but is not marketed in the United States. Hexaxim, made by Sanofi Pasteur, was licensed by the European Medicines Agency in 2013. Vaxelis, produced by MCM (a joint venture between Sanofi and Merck), was licensed in Europe in 2016 and approved by the U.S. FDA in 2018, making it the first and currently only hexavalent vaccine available in the U.S.
The specific formulations differ slightly between products. For example, some contain two purified pertussis proteins while others contain three or four. All three vaccines contain inactivated polio strains 1, 2, and 3, and all use a version of the hepatitis B surface protein grown in yeast.
When It’s Given
In the United States, Vaxelis is approved for children from 6 weeks through 4 years of age (before the fifth birthday). It can be used for the first three doses in the DTaP, polio, and Hib series, and for any hepatitis B dose after the birth dose. A separate hepatitis B shot is still given at birth, so the hexavalent vaccine doesn’t replace that initial dose.
The WHO has also prequalified a whole-cell pertussis hexavalent vaccine for use in national immunization programs worldwide, recommending it follow the same schedule as the pentavalent vaccine already used in many countries: doses at 6, 10, and 14 weeks, or 8, 12, and 16 weeks depending on national policy.
Why Combine Six Vaccines in One
The main advantage is practical: fewer needle sticks for your baby. Instead of receiving separate injections for each disease at each visit, a single shot covers all six. This also simplifies the immunization schedule, reduces the number of clinic visits, and makes it more likely that children complete their full vaccine series on time. In countries with complex logistics for vaccine storage and delivery, fewer vials to manage can meaningfully improve coverage rates.
Combining antigens isn’t as simple as mixing six vaccines together, though. When different antigens, preservatives, and stabilizers are combined, they can interact in ways that reduce the potency of individual components or create instability. Manufacturers spend years testing specific formulations to ensure that each of the six components triggers a strong enough immune response on its own. One challenge, known as immune interference, is that the body’s response to one antigen can temporarily dampen its response to another. In early studies, slight interference was observed in peak responses to the hepatitis B and diphtheria components, but these differences disappeared at later measurement points and didn’t affect overall protection.
How Well It Works
Hexavalent vaccines produce strong protective immune responses across all six components. The hepatitis B component is particularly effective, with protective rates between 98% and 100% when measured one to three months after completing the primary series. Protection against the other five diseases is similarly robust, matching the immune responses seen with individual or lower-valency vaccines.
One area that has received scrutiny is the pertussis component. Some hexavalent formulations contain only two purified pertussis proteins, while standalone pertussis vaccines may contain three or more. Whether this difference has any meaningful impact on real-world protection is still being evaluated, but the vaccines meet regulatory thresholds for immune response.
Side Effects
The most common reactions are the same ones you’d expect from any childhood vaccine: pain or redness at the injection site, fever, and increased crying. These are typically mild and resolve within a day or two.
Prelicensure studies found that the hexavalent vaccine produced a slightly higher rate of fever compared to pentavalent vaccines (which cover five diseases instead of six). This is consistent with the general pattern that more antigens can trigger a somewhat stronger inflammatory response, but the fevers observed were within the range considered normal and manageable with standard comfort measures.
Postmarketing surveillance through the Vaccine Adverse Event Reporting System has continued to monitor for rare or unexpected reactions since the vaccine entered routine use, and the safety profile has remained consistent with what was seen in clinical trials.
Who Should Not Receive It
Children who have had a severe allergic reaction to a previous dose of any of the six component vaccines, or to any ingredient in the specific hexavalent product, should not receive it. Because the vaccine contains a pertussis component, children who experienced a serious neurological event (such as prolonged seizures or encephalopathy) within seven days of a prior pertussis-containing vaccine are generally not candidates. In these cases, doctors can still give the remaining components as separate shots, skipping only the pertussis portion.
The vaccine is not approved for children under 6 weeks of age or for anyone 5 years and older. It also cannot replace the hepatitis B birth dose, which is given separately in the first 24 hours of life.