The full name of the 5-in-1 vaccine used in the UK was DTaP/IPV/Hib. This stands for ‘Diphtheria, Tetanus, acellular Pertussis, Inactivated Polio Vaccine, Hib (Haemophilus influenzae type b)’. The 5-in-1 protects against these five different diseases.
The introduction of a vaccine against these five diseases resulted in a remarkable decline in the number of deaths. The table below shows the average number of deaths in the UK each year, before and after, introduction of the vaccine:
Source: Public Health England and the Health Protection Agency archive
The 5-in-1 includes the acellular pertussis (whooping cough) vaccine - the ‘aP’ in ‘DTaP’. This uses three or five proteins from pertussis bacteria, which help provide protection against whooping cough. Using these purified proteins reduces the chance of more severe side effects such as high temperatures, screaming episodes, and hypotonic-hyporesponsive episode (read about HHE in 'Safety and side effects' section above). By comparison, the whole cell (wP) vaccine contains thousands of components and has a greater chance of side effects.
The Hib part of the 5-in-1 is a conjugate vaccine. Sugars taken from the capsule around the Hib bacteria are joined to a non-toxic protein produced by tetanus bacteria. The protein helps to stimulate the immune system in a broader way so it responds well to the vaccine. This gives a better immune response in individuals of all ages.
The polio component is made from several virus strains, grown in the laboratory using animal cells. The virus strains are inactivated (killed) with formaldehyde. They are then adsorbed onto adjuvants, which are ingredients to help the vaccine create a stronger immune response. For polio, the adjuvants are either aluminium phosphate or aluminium hydroxide. See more information on animal cell strains in vaccine production. As the polio vaccine is inactivated, it cannot cause polio. This was a very small risk with the live, oral polio vaccine used in the UK until 2004.
The diphtheria part of the vaccine is a toxoid vaccine. The diphtheria toxin is purified, inactivated (killed) and treated with formaldehyde to convert it into harmless diphtheria toxoid. For the most part, the vaccine is not given on its own, but in combination vaccines, for example with tetanus toxoid and pertussis.
As with diphtheria, the tetanus component is a toxoid vaccine, treated with formaldehyde, then absorbed onto an adjuvant to improve people’s immune response to the vaccine.
Countries which used the same 5-in-1 vaccine as the UK may have had different vaccination schedules. In the UK, the three doses were given as close together as possible to give babies early protection from pertussis (whooping cough). This disease can be particularly severe in very young babies, so the earlier they are protected the better.