Side effects in clinical trials

Clinical trials are carefully designed to minimise the risks and maximise the benefits to everyone taking part, whichever treatment they receive. Some trials will involve very little risk. Researchers should explain to you what they already know about possible side effects to help you decide whether, or not, to enrol your child. This will depend very much on the type of treatment being tested, so you will need to ask questions about the specific trial. Of course, it can be worrying hearing about all the possible side effects. However, it is important to bear in mind that usually few people will experience them.
Most parents said that possible side effects of treatment were explained to them and they were able to ask questions and raise any concerns. (See also ‘Information given to parents when invited to enrol their child’.)

Knowing the side effects of growth hormones, Lisa was able to make an informed decision to enrol…

Age at interview 37

Gender Female

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It was explained that the risk of side effects were very low.

Age at interview 32

Gender Female

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Possible side effects of having the swine flu vaccine were explained in great detail. Knowing…

Age at interview 44

Gender Female

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Some parents in vaccine trials remembered the recent debate on the MMR vaccine. (See also Immunisation: parents’ concerns about MMR). Catherine’s son was born prematurely and she decided not to enrol her son in a five-one vaccine trial.

Catherine understands the need for vaccines and supports clinical trials, but due to concerns…

Age at interview 27

Gender Female

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Lenas daughter experienced a high temperature and soreness after the second vaccine injection…

Age at interview 44

Gender Female

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However, most people with children in vaccine trials reported few side effects, mostly were minor symptoms such as soreness and a raised temperature. Knowing what to expect was reassuring for parents, as in Lena’s case, they didn’t feel the need to phone the researchers or seek further medical advice.
One of the main reasons for carrying out trials is to find out about side effects and measure how serious they are. Children who take part in trials are monitored carefully. They will often require regular tests and may be asked questions about how they feel. Lucinda was initially concerned that her son would not be able to tell the doctors about any side effects.

Lucinda was worried that her son would find it hard to describe any side effects of the treatment…

Age at interview 37

Gender Female

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Jessica, a research nurse, says it is really important that parents and children inform the…

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Jo rang the doctors immediately when her son began to change his behaviour.

Jo rang the doctors on two occasions about possible side effects and received an immediate response.

Age at interview 28

Gender Female

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Lucindas son was happy to stay in the trial. So far hes had no major side effects, but if he…

Age at interview 37

Gender Female

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It is important to report any side effects promptly as this tells the researchers something important about treatments being tested. They will be able to help manage the side effects, or advise you whether your child should stop taking part. As Jo (above) says it is not always clear to parents whether symptoms are a result of the trial or just coincidence, but it is better to tell the doctors. Withdrawing from a trial because of side effects is entirely reasonable and no-one should feel they have to stay in for the sake of the trial or that they have failed if they pull out. (See also ‘Withdrawing your child from a trial’.)
One parent talked about her son’s experiences of side effects while taking part in a Phase 1 trial. However, Alison’s son is at an age when he can consent to take part and this has been worrying for her at times.

Alison wanted her son to let the hospital know about a possible side effect of treatment; taking…

Age at interview 49

Gender Female

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Having a good relationship with her son has helped in supporting him through clinical trials.

Age at interview 49

Gender Female

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When your child consents to a trial it is up to him or her, to report symptoms or possible side…

Age at interview 49

Gender Female

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In all trials the treatment may cause side effects or problems that doctors cannot predict. This may happen more often when less is known about the treatment being tested as in the Phase 1 trial for Alison’s son. (See also ‘When the trial ends: feedback of trial results’.)

Anyone taking part in a drug trial should also be told about other drugs or other substances, such as food or herbal remedies, which may interact with the trial drug and cause side effects. Sometimes trials that do not involve drugs can also have side effects, for example minor surgery or tests that may leave your child feeling uncomfortable. Several parents said their children found blood tests and injections difficult. This is discussed in ‘What is involved in a trial: appointments and monitoring‘).