What parents need to know
1. How do vaccines work in the human body?
Vaccines produce their effect by educating the body on how to defend when specific germs (such as viruses or bacteria) enter the body. Vaccines comprise a small number of germs that have been weakened or killed. When a vaccine is given, it makes the body’s defence system develop a response to that germ and the immune system memorizes it. If the same germ infects the body in the future, the immune system recognizes and fights against it.. As a result, the person does not become ill or has a a milder infection in the future. Keep in mind that the body needs a normal functioning immune system for this process to take place when a vaccine is given.
2. Can we give vaccinations to children with cancer during cancer treatment?
We should not give certain vaccines to children during cancer treatment.
3. Why should we not give childhood cancer patients certain vaccines?
There are multiple reasons for this. Childhood cancer patients often have weakened immune systems during cancer treatment.
A vaccine requires a good immune system to process the vaccination effect. So it may not be effective when given to someone receiving treatment for cancer.
Some vaccines that contain weakened (attenuated) viruses can cause infection in children with ongoing cancer treatment if they receive them because their immunity is not functioning normally.
4. What are the vaccines that we should not give to children on cancer treatment?
Routine vaccines that contain live or weakened (attenuated) virus should not be given to children with a weakened immune system. They include following vaccines:
- Oral polio
- MMR (measles, mumps, rubella)
- Varicella (chickenpox)
- Rotavirus
- Oral Typhoid vaccine
5. What vaccines are recommended during cancer treatment?
Children receiving treatment for cancer can generally receive most routine vaccines except the live and live attenuated virus vaccines.
However, because of the child’s weakened immune system, the shots given during this time need to be repeated after finishing cancer treatment as they might not be effective. Neverthless, they may provide some level of protection.
Many internationally recognized organisations recommend giving an annual inactivated flu vaccine to all children older than 6 months including those receiving treatment for cancer.
The vaccine may be given at least 2 weeks before chemotherapy or between chemotherapy cycles.Those who have not received influenza vaccine previously should be administered a second vaccine dose at least four weeks later.
Avoid vaccination when the patient is receiving steroids (the immune response will be suboptimal) or when the patient is neutropenic (neutrophil count <0.5).
6. What are the vaccines household contacts like siblings and parents can take?
Siblings and adults who live with a childhood cancer patient should be fully vaccinated to minimize the risk of exposing the child to a vaccine-preventable disease. The exception being that they should not receive a live vaccine e.g vaccine for oral polio.
General recommendations are:
Non-live vaccine: All non-live vaccines should continue as per the national immunisation schedule in siblings of children on cancer chemotherapy.
Inactivated Influenza vaccine is strongly recommended for all household contacts, annually.
Live, attenuated varicella vaccine and MMR should not be given to patients but is encouraged for all household contacts to reduce the chances of exposure to an infection.
As a precautionary measure, any person who develops a vesicular rash after receiving VZV vaccine should avoid direct contact with the patient until the rash is dry and crusted.
Rotavirus vaccine: Is given to infants aged 6-24 weeks; it should not be given to the patient but can be given to the siblings. There is a potential for transmission, from the infant to the immunocompromised contacts, through the faecal-oral route, for at least 14 days post-vaccination. However, vaccination of the infant will offer protection to household contacts from wild-type rotavirus disease and outweigh any risks from transmission of the vaccine virus to any immunocompromised person.
7. When can children resume vaccinations after treatment for cancer?
In general, children may resume vaccinations 6 months after the end of standard chemotherapy.
Patients who received some routine vaccinations before or during chemotherapy should have a catch-up schedule, as if they had not been given any vaccines. This may be required because we do not know whether the vaccines were effective or not during the first administration
Children who completed their routine vaccination cycles before their cancer treatment can be given a booster dose of the vaccinations.
Transplant patients may have to wait longer; usually one year . They will need to receive all their vaccinations because the transplant process has wiped out the immune system they had before the transplant.
