More children are receiving delayed vaccinations due to parental intent, barriers to health care, the COVID-19 pandemic or other barriers to immunization. Now, experts say delaying measles vaccination in children could increase a child’s chances of a febrile seizure.
Researchers in a study, which emphasised the importance of following the timing of immunisation of children, said delaying certain routine immunisations past the first 15 months of life could boost the risk of fever-related seizures.
Over two million deaths are delayed through immunisation each year worldwide. Despite this fact, vaccine-preventable diseases remain the most common cause of childhood mortality with an estimated three million deaths each year.
They had studied vaccination records of over 323,000 U.S. children from 2004 to 2008 to know if babies whose vaccinations were delayed were more likely to develop fever-related seizures. It found that when vaccination is postponed, the risk of fever-related seizures rises twofold. But the risk is still really low.
The timing of vaccinations during the first year of life didn’t affect seizure rates. But delaying a measles-mumps-rubella immunization until 16 to 23 months boosted the risk of seizure from about 1 in 4,000 doses to 1 in 2,000 doses. The study was published online on May 19 in Pediatrics.
The seizures only last one to two minutes, causing an altered state of consciousness, trembling and possible loss of bladder and bowel control. Typically, the seizures have no lasting effect.
The vaccines in question are the combination measles-mumps-rubella and the newer combo immunisation for measles-mumps-rubella plus chickenpox (varicella).
These potentially serious childhood diseases are very contagious. According to the U.S. Centers for Disease Control and Prevention, the first dose of either vaccine is given at 12 to 15 months and a second dose at 4 to 6 years.
The timing of vaccinations during the first year of life didn’t affect seizure rates. But delaying a measles-mumps-rubella immunisation until 16 to 23 months boosted the risk of seizure from about 1 in 4,000 doses to 1 in 2,000 doses.
Sometimes, fevers can cause a child to experience spasms or jerky movements called seizures. Seizures caused by fever are called “febrile seizures.” They are most common with fevers of 102°F (38.9°C) or higher, but they can also happen at lower body temperatures or when a fever is going down. Most febrile seizures last for less than one or two minutes.
Previous studies have found that measles-containing vaccines are linked with a small increased risk of seizures brought on by fever, called febrile seizures, one to two weeks after vaccination. The reason for the link is not known, but scientists suspect an increase in virus replication occurring in this one- to two-week time period may cause fever in some children.
Dr Joy Alejo, a consultant paediatric neurologist at the University College Hospital, Ibadan, however, assured that delaying the child’s measles-related vaccine would not raise the child’s risk of seizures.
She declared: “A child that has just been vaccinated may have a fever in response to the vaccine. Anything that will cause a fever in a child can cause febrile convulsion. If that child already has the tendency to have a febrile seizure, whether you give him the measles-related vaccine at 10 months or at 12 months, he could still have a fever and then convulse. It is not the vaccine itself that causes febrile seizures.
“Indeed the childhood vaccines that have been implicated are things like diphtheria, tetanus, and pertussis (DTP) vaccine and Pentavalent vaccine which contains 5 different vaccines (diphtheria, acellular pertussis, tetanus, inactive polio, Haemophilus influenzae type B, and conjugate pneumococcal vaccine).
“Even if the child has taken the other vaccines and did not have a fever, by the time he takes the Pentavalent vaccine, they will usually have a fever because it is a lot of antigens that you are bringing into the body to be prepared in case the infection comes.”
According to her, given that children may have a fever in response to the vaccine, parents are always advised to give antipyretics like paracetamol to children for a day or two afterwards.
Meanwhile, Dr Babatunde Ogunbosi, a consultant paediatrician at UCH, Ibadan, if children are not vaccinated timely, they stand the risk of contracting these infections the vaccines were supposed to protect them against.
According to him, “measles is a highly contagious condition, especially in areas where the disease is still very endemic. So it is not advisable that people delay the measles vaccine except there are contraindications to doing so.
“When a child develops measles, there can be complications. Its complications include blindness, ear infections, diarrhoea, pneumonia and encephalitis. Encephalitis is an infection that can cause brain swelling, including seizures. All of that can be quite fatal. So, in general, it’s not advisable to delay measles vaccine.”
It is well evident that the consequences of not giving vaccines are far more than the adverse events. So Vaccinations should be performed regardless of age; medically attended febrile seizures following immunization with measles-containing vaccines are rarely encountered.