Over the last 50 years there has been a big increase in the number of vaccines given to children. If all these vaccines were given separately, each child would have to receive a large number of injections. Combination vaccines such as the 5-in-1 and the MMR have been developed to help reduce the number of injections needed. Even so, babies and children often receive several vaccines at once. For example, a 2 month old baby will receive the 5-in-1, PCV, Rotavirus and MenB vaccines at the same time.
Parents sometimes worry that their child’s immune system will not be able to cope with receiving several vaccines at once. In fact, even a tiny baby’s immune system can cope easily. From birth onwards, a baby comes into contact with millions of germs every day. Babies' immune systems are working all the time to protect them against bacteria and viruses in the environment. Vaccines represent a very small challenge to the immune system when compared to this. Each millilitre of blood contains ten million B cells, the white blood cells that are associated with the immune response. It is estimated that this would be enough to cope with thousands of vaccines at a time. Even a tiny baby’s immune system is not stretched at all by receiving several vaccines at once. It is not a good idea to delay vaccinations to ‘spread the load’, because it leaves the baby unprotected against dangerous diseases for longer.
Although the number of vaccines has increased, the number of antigens in vaccines has actually gone down dramatically. Antigens are the active ingredient - the parts of the vaccine made from viruses or bacteria which challenge the immune system so that it makes antibodies to fight the disease. In 1960 there were 3200 antigens in vaccines that protected against four diseases. By 2012, vaccines contained just over 60 antigens but protected against 11 diseases.
Read Addressing Parents’ Concerns: do multiple vaccines overwhelm or weaken the infant’s immune system? , a 2002 study into the effect of multiple vaccines on the child's immune system.
In the short film below, Professor Sophie Hambleton talks about the safety of combination vaccines.