The best way to ease babies' pain during vaccinations may be to give them a sip of sugar and rub anesthetic cream on the injection site before they get shots, a recent experiment suggests.
Sugar solutions and lidocaine cream have long been among the options some doctors use to make vaccinations less miserable for babies and parents alike. But there's not a lot of evidence to suggest exactly which combinations of pain relief might work best, researchers note in the Canadian Medical Association Journal.
To determine the most effective pain relief option, researchers randomly assigned 352 healthy babies to one of four groups for all of their vaccinations over the first year of life: video instruction for parents on how to soothe infants during shots; videos for parents and a sugary drink for babies; videos, sugary drinks and anesthetic cream; and a control group that didn't get any help with pain.
"We only found a benefit from the combination of lidocaine with sugar and the parent instructional video," said lead study author Dr. Anna Taddio, a pharmacy researcher at the University of Toronto.
"None of the other three treatment groups were different in terms of the pattern of pain responses observed in the infants," Taddio added by email. "This suggests that the only effective pain intervention was the lidocaine."
For the experiment, every parent watched a video, but participants in the control group saw a video that didn't include any instructions on infant pain relief.
Similarly, all babies received a drink and some cream regardless of the group they were in. This way, participants didn't know whether infants actually got sugar water or lidocaine.
Researchers scored infant pain during vaccinations by observing how much they grimaced, cried or made movements suggesting pain like flailing their arms or kicking their legs. They also asked parents to rate babies' pain based on their observations of the infants during vaccinations.
When used consistently during vaccinations over the first year of life, only the regimen including lidocaine showed a benefit on acute pain when compared with the other alternatives, the study found.
None of the regimens appeared to alter the time it took babies to recover from pain after their shots.
In addition, pain changed as babies aged, steadily decreasing over the first six months of life and then increasing at 12 months.
Because parents in all of the study groups could hold babies to comfort them during vaccinations, it's possible that this made it difficult to detect any benefits associated with showing parents instructional videos or giving babies sugar water, the authors note.
Another limitation of the study is the potential for wide variation in how parents implemented tips from the instructional video, which may have made it hard to detect benefits from suggested interventions like rhythmic breathing, cuddling and distracting babies during shots, the authors also note.
The timing and dosing of sugar water, given all at once roughly one to two minutes prior to shots, may have also made this option appear less effective, said Denise Harrison, a researcher at the Children's Hospital of Eastern Ontario and the University of Ottawa in Canada.
"In babies beyond the newborn period, the analgesic effects wear off quickly," Harrison, who wasn't involved in the study, said by email.
"The dose of sugar water needs to be given in small portions around one minute before the procedure, then again just before each injection," Harrison said. "Using these recommended times in the study may have changed the results."
Proper pain relief during vaccinations can help avoid babies developing negative associations with needle sticks that make shots harder to deliver as they get older, Harrison added. It can also make parents more likely to stick to recommended childhood vaccination schedules.
"Although results are not compelling from this current study, we still know what treatments help babies during vaccinations," Harrison said. "These include breastfeeding, sugar water, anesthetic creams as well as distraction."