Australian researchers are trying to take the sting out of the jab ahead of the expected mass global rollout of COVID-19 vaccines.
The scientists from Queensland's James Cook University have tested the efficacy of cooling agents on vaccination pain in 13 trials involving 700 children and 800 adults.
They found "cold sprays", known as vapocoolants, or ice delivered onto the skin just before needle insertion reduced vaccination-related pain in all adult studies and six paediatric trials.
Lead researcher Clare Heal, of the university's college of medicine and dentistry, said pain reduction rose as skin temperature approached 0C.
"Cooling techniques are considered to be cost-effective, easy to use and have few, if any, side effects when applied correctly," Professor Heal said in a statement on Wednesday.
"Vapocoolants have the advantage of providing instantaneous cooling effects to the skin."
Researchers compared the results against other techniques including skin numbing cream, breastfeeding for those under two, distraction and tactile stimulation.
Injection pain and anxiety is a reason why some people avoid vaccinations, Prof Heal said, and adequate pain management strategies should form part of every jab.
"Vaccinations save up to three million lives each year and are the cornerstone of herd immunity," she said.
"So anything we can do to reduce the pain and anxiety of intra-muscular vaccinations and protect immunisation rates warrants further investigation."
The only ineffective vapocoolant technique was the application of ice packs on children.
Although the paediatric study findings were inconclusive, a review concluded the use of the cold sprays and ice works for adults.
However, Prof Heal said more research is required.
"More rigorous and larger-scale randomised control trials are needed to determine the effectiveness and applicability of skin cooling techniques," she said.
Australian Associated Press