A study looking at a vaccine to prevent infection in children with acute lymphoblastic leukaemia

Cancer type:

Acute leukaemia

Acute lymphoblastic leukaemia (ALL)

Blood cancers

Children's cancers

Leukaemia

Status:

Results

Phase:

Other

This study was done to find out the best time to give Prevenar-13 to help prevent infections. It was for children with acute lymphoblastic leukaemia (ALL) who were having or had recently finished treatment.

The study was open for people to join between 2010 and 2014. The team published results in 2020.

More about this trial

Our immune system helps us fight infections. Chemotherapy can weaken the immune system. This means people having chemotherapy are more likely to get an infection.

Doctors know that children who have chemotherapy for ALL have an increased risk of an infection called pneumococcus. This can be the case for months after they finish treatment. So they have a vaccine to help prevent this infection.

When this study was done, children in the UK often had the vaccine about 6 months after they finished treatment. But this was different in other countries. And the researchers wanted to find out the best time to give it.

In this study the researchers looked at a vaccine called Prevenar-13 (PCV13). The children who took part had the vaccine either:

during the last few months of chemotherapy
a month after they finished chemotherapy
6 months after they finished chemotherapy

The research team measured the number of various immune system cells to see if they changed. And how long the changes lasted.

The main aim of this study was to find out the best time to give Prevenar-13 to help prevent pneumococcal infection in children with ALL.

Summary of results

The research team found that it is best to give the vaccine soon after finishing chemotherapy.

Study design
The children in this study had acute lymphoblastic leukaemia (ALL). Some were coming to the end of their planned treatment. Some had recently finished treatment.

The research team took blood samples to measure different immune system cells:

before they had the vaccine
4 weeks after they had the vaccine
a year after they had the vaccine

Results
A total of 118 children aged between 2 and 17 joined this study:

39 had the vaccine during treatment
40 had the vaccine soon after finishing treatment
39 had the vaccine 6 months after finishing treatment

Diagram 1

The research team measured the immune cells in blood samples before and after the vaccine injection.

The results were similar for:

those who had the injection soon after treatment, and
those who had the injection 6 months after treatment

They found that the immune system had responded to the vaccine 1 month after the injection in:

5 out of 39 children (13%) who had the vaccine during treatment
22 out of 37 children (59%) who had the vaccine soon after treatment
21 out of 37 children (57%) who had the vaccine 6 months after treatment

Bar Chart 1

And that the immune system response was still there a year after the injection in:

no one who had the vaccine during treatment
11 out of 29 children (38%) who had the vaccine soon after treatment
13 out of 30 children (43%) who had the vaccine 6 months after treatment

Bar Chart 2

They also looked at levels of different immune cells in more detail. This showed that the levels of some immune cells fell during treatment and stayed low for months afterwards. But the levels of other immune cells fell during treatment and went back to normal quite quickly.

Conclusion
The research team concluded that it is best to give the Prevenar-13 vaccine to children soon after they finish treatment. They suggest that UK guidelines are updated to recommend this.

Where this information comes from
We have based this summary on information from the research team. The information they sent us has been reviewed by independent specialists (peer reviewed Open a glossary item ) and published in a medical journal. The figures we quote above were provided by the trial team who did the research. We have not analysed the data ourselves.