Figures show the number of children under-five receiving injections over the past year, including the MMR vaccine have gone down.
Most vaccines are given to children before they reach age five.
The NHS data shows a drop across England in 2018-19 in vaccination rates compared to the previous year.
Children receiving the first dose of the measles, mumps and rubella (MMR) dropped from 91.2% to 90.3%.
There are 10 vaccines given in total, providing protection against diseases such as tetanus, polio and meningitis.
MMR is given in two doses - one just after a child's first birthday and then a second dose before school.
Certain people can't be vaccinated because of their age or because they have other health problems and some parents choose not to have their children vaccinated.
A vaccination is a treatment which makes the body stronger against a particular infection.
Vaccines teach your immune system how to create antibodies that protect you from diseases.
Once your immune system knows how to fight a disease, it can often protect you for many years.
If people stop having vaccines, it's possible for infectious diseases to quickly spread again
Earlier this year, the UK lost its measles elimination status, along with four other countries, according to the World Health Organisation.
The target for vaccination is 95% uptake as that is the level at which herd immunity is achieved, which means the disease cannot circulate because of the high levels of protection.
The data showed that no part of England has managed the 95% target for the first dose.
Health Secretary Matt Hancock said the situation was "unacceptable".
"Everyone has a role to play in halting this decline.
"The loss of our measles-free status is a stark reminder that devastating diseases can, and will, resurface.
"We need to be bold and I will not rule out action so that every child is properly protected."