Understanding Pentavalent and Hexavalent Vaccines

Sabin Vaccine Institute Director of Research Kate Hopkins, PhD, breaks down the trend towards newer hexavalent vaccines in many national childhood immunization programs. Sabin’s Vaccine Acceptance & Delivery initiative and its research consortia are working with Gavi, the Vaccine Alliance to collect real-world planning and implementation data from the first countries switching in Africa, to support subsequent hexavalent vaccination decision-making and programmatic roll-out globally.

What are pentavalent and hexavalent vaccines?

The pentavalent (penta) vaccine offers protection from the following five antigens (substances the body recognizes as foreign — like a virus or bacteria— that can trigger an immune response): diphtheria, tetanus, pertussis, hepatitis B, and Haemophilus influenzae type B (Hib).

The hexavalent (hexa) vaccine takes it one step further and includes protection from polio.

How long have they been used?

The penta vaccine was first prequalified by the World Health Organization (WHO) in 2001. It rolled out globally over a decade, starting with the U.K. in 2004. From 2005, WHO, in collaboration with Gavi, the Vaccine Alliance (Gavi), UNICEF, and other partners, began actively supporting country-level introduction of penta vaccines, especially in low-income countries. By 2014, nearly all Gavi-supported countries had penta integrated into their national immunization programs (NIPs).

Hexa immunization reached its prequalification around 2004, with some of the earliest adoption occurring in high-income countries (Australia) from 2005.  Gavi has supported the switch from separate penta and polio vaccination to hexa vaccine since 2023. The first Gavi-eligible countries to make the switch will be Mauritania and Senegal – both countries switched on July 1, 2025.

Why are all six put into one vaccine?

Polio eradication is of major global concern, and the WHO recommends a three-dose series of inactivated polio vaccine (IPV1, IPV2, and IPV3) starting between four to six weeks of age, with four-week intervals between vaccinations.

Globally, IPV1 coverage for 2023 was estimated at 83%, with 40 countries below 80% coverage; and 36 countries— 21 of which are in the WHO AFRO region— have yet to introduce IPV2.  By adding the polio vaccine to the one most-utilized childhood vaccine, the expectation is that coverage will increase.

Hexa vaccination provides an opportunity for countries to provide protection against more diseases through a single vaccination series, creating programmatic efficiencies.

What are the specific benefits of transitioning from pentavalent (vaccines that protect against five diseases) to hexavalent vaccines?

The proposed benefits for countries transitioning from the separate penta and polio vaccines (IPV) to hexa include:

• Increasing programmatic efficiency by reducing the number of vaccinations (from six to three) in childhood immunization programs, with potential cost-savings related to vaccination supplies, cold chain storage, open vial wastage and health worker time-tracking and administering vaccines
• Supporting polio eradication by facilitating IPV coverage and integration of IPV into national immunization programs

What are some of the challenges?

The challenges of this specific vaccination transition for resource-constrained countries are largely undocumented and need to be studied. Sabin has been funded by Gavi to lead a Consortium of research partners to obtain information around the challenges and bottlenecks experienced during implementation for the first Gavi-eligible countries.

We will collect real-world implementation data on the complexity, practical and logistical considerations, the three-step switch timeframe (withdrawing separate penta and polio immunizations and introducing hexa vaccination) and actual costs of switching to a hexa vaccination program. The lessons learned will inform planning and implementation for future countries making the switch, as well as Gavi co-financing policies.

What role could hexavalent vaccines play in achieving the WHO’s Immunization Agenda 2023, particularly in reaching zero-dose and under-immunized children?

Immunization targets set to be achieved by 2030 through the Immunization Agenda (IA2030) include achieving 90% coverage for essential vaccines given in childhood and adolescence; a 50% reduction in the number of children completely missing out on vaccines; and completing 500 national or subnational introductions of new or under-utilized vaccines.

With hexa vaccination including more antigens than penta, by design it is meant to increase coverage of essential vaccines through one immunization series. In particular, it integrates protection for polio into national immunization programs. Hexa vaccination will stand in place of IPV2 introduction, streamlining immunization programming.

So, what does this mean? Switching from separate penta plus IPV vaccination to hexa:

1. Reduces the number of injections, which eases the burden on the child, caregiver, and health worker; particularly in the context of vaccine hesitancy. It could help us reach zero-dose and under-vaccinated children if it increases parental acceptance.
2. Creates potential cost savings linked with fewer doses administered, required syringes and waste management, cold chain costs, etc.
3. Supports polio eradication efforts by ensuring streamlined integration of IPV into routine immunization, and in doing so, may decrease strain on an already overworked healthcare system and hopefully reach more under-immunized children.