A pediatrician holds a dose of the measles-mumps-rubella (MMR) vaccine at his practice in Northridge, Calif. on Jan. 29, 2015. THE CANADIAN PRESS/AP, Damian Dovarganes

A pediatrician holds a dose of the measles-mumps-rubella (MMR) vaccine at his practice in Northridge, Calif. on Jan. 29, 2015. THE CANADIAN PRESS/AP, Damian Dovarganes

Infants more vulnerable to measles than previously thought: Canadian study

Babies typically don’t receive the measles vaccine until they are 12 months old

A new study suggests infants are more vulnerable to measles infection than previously thought.

The findings debunk notions that most babies are protected for much of their first year by maternal antibodies passed on through pregnancy.

In fact, Toronto researchers from the Hospital for Sick Children and Public Health Ontario say the vast majority of 196 infants they studied were susceptible by three months of age.

And none of the infants were immune at six months.

Babies typically don’t receive the measles vaccine until they are 12 months old. That results in a wide susceptibility gap that the study’s senior author called “quite alarming.”

Shelly Bolotin, a scientist at Public Health Ontario, said the findings underscore the need for everyone to keep their immunization up-to-date to protect the most vulnerable members of the population.

“This is really troubling because measles is a serious disease, and it can be quite serious in infants,” said Bolotin, also an assistant professor at the Dalla Lana School of Public Health and the Department of laboratory medicine and pathobiology at the University of Toronto.

“It can be absolutely devastating and we need to make sure that we are protecting our most vulnerable members of our population — infants.”

The study was published online Thursday and appears in the December edition of the American Academy of Pediatrics journal, Pediatrics.

It found that 20 per cent of one-month-old infants had antibody levels below the protective threshold and 92 per cent of three-month-old babies has levels below the threshold.

Bolotin said researchers already knew infant immunity declines in the first six months of life, but they did not expect such a rapid drop.

“We were surprised to see that waning or that lack of protection start earlier,” said Bolotin, who collaborated with lead author Dr. Michelle Science, infectious disease specialist at Sick Kids and also an infection control physician at Public Health Ontario.

She said the assumption that babies are protected longer is based on studies conducted in places where measles remains prevalent. In those regions, mothers have more robust antibody levels to pass on to their child because their immunity comes through natural infection and is repeatedly boosted by continual exposure to measles.

In contrast, most Canadian women of childbearing age are immune through vaccination because Canada eliminated measles in 1998. Although vaccination rates are high here, immunization through vaccine is associated with lower antibody levels than natural infection.

READ MORE: B.C.’s measles vaccination program gains traction

Bolotin said the Toronto study is unique in measuring antibodies at each month of an infant’s life from birth to 12 months. Previous research has focused on measuring immunity levels among babies at birth or those older than six months.

A companion paper written by two other experts that also appears in Pediatrics raises the question of whether it’s time to consider changing the vaccine schedule. It concludes there’s no reason to vaccinate earlier, despite ongoing outbreaks in the United States.

Bolotin acknowledged this is a challenging question for policy makers who must weigh the risk of infection against the best time to vaccinate children, whose immunity system is still maturing.

Infants between six and 11 months who travel to regions where measles is endemic are encouraged to receive an early dose of the vaccine in addition to their regular 12-month dose, but otherwise, all provinces in Canada recommend the measles, mumps, and rubella vaccine (MMR) at 12 months of age.

The schedule for a second dose of the vaccine varies across the country.

The Pediatrics commentary suggested early vaccination may actually hinder the efficacy of a later dose, resulting in lower levels of the antibody compared with children who first get the vaccine at 12 months.

“Early vaccination may also alter response after re-vaccination, leading to lower levels of the antibody compared with children who are vaccinated for the first time during the second year of life,” they state, citing one study that looked at immunity in children aged five to 10, and another published earlier this year that looked at short- and long-term impacts on children in the Netherlands.

As of late last week, Bolotin said Canada has seen 112 cases of measles this year, the vast majority of them imported or import-related.

Measles can cause severe complications including pneumonia, encephalitis and death.

Cassandra Szklarski, The Canadian Press


Like us on Facebook and follow us on Twitter.

Get local stories you won't find anywhere else right to your inbox.
Sign up here

Just Posted

Interior Health has declared the Cariboo Chilcotin a community cluster. (Angie Mindus photo)
Interior Health declares Cariboo Chilcotin region a COVID-19 cluster, 215 cases since Jan. 1

Most cases are related to transmission at social events and gatherings in Williams Lake

A boil water advisory has been lifted for residents in Williams Lake as of Thursday, Jan. 21. (File photo)
Boil water advisory lifted for Westridge, golf course, Terra Ridge area

Potable water sample tests showed water safe to consume

Aside from being a retired librarian and member of the Cariboo Chilcotin Partners for Literacy, Lil Mack advocates or literacy with her own little book box out front at her Ninth Avenue North home. (Monica Lamb-Yorski photo - Williams Lake Tribune)
Our Hometown: Advocating for literacy

Lil Mack has been with Cariboo Chilcotin Partners for Literacy since its inception

The City of Williams Lake is awaiting the arrival of seven terrain park features typically found at ski hills to create more winter recreational opportunities in Boitanio Park. (Arena Snowparks Instagram)
City shows cool side with winter, Boitanio rail park

“We’re just waiting for their arrival and a little more snow,” Atkinson said.

Williams Lake First Nation Chief Willie Sellars provides a community COVID-19 update from his home Wednesday, Jan. 20. (Williams Lake First Nation Facebook image)
WLFN chief reports 11 members fully recovered from COVID-19

23 active cases remains, says Chief Willie Sellars

Maj.-Gen. Dany Fortin, vice-president of logistics and operations at the Public Health Agency of Canada, speaks at a news conference on the COVID-19 pandemic in Ottawa, on Friday, Jan. 15, 2021. THE CANADIAN PRESS/Justin Tang
B.C. records 500 new COVID-19 cases Wednesday, 14 deaths

Outbreak at Surrey Pretrial jail, two more in health care

The top part of the fossil burrow, seen from the side, with feathery lines from the disturbance of the soil – thought to be caused by the worm pulling prey into the burrow. (Paleoenvironntal Sediment Laboratory/National Taiwan University)
PHOTOS: SFU researchers find evidence of ‘giant’ predatory worms on ocean floor

Fossils found the prove the existence of an ancient Taiwanese worm as long as two metres

Cannabis bought in British Columbia (Ashley Wadhwani/Black Press Media)
Is it time to start thinking about greener ways to package cannabis?

Packaging suppliers are still figuring eco-friendly and affordable packaging options that fit the mandates of Cannabis Regulations

RCMP officers provide policing for 63 B.C. municipalities under a provincial formula based on population. (Black Press file photo)
B.C. communities warned of upcoming RCMP unionization costs

Starting salaries for city police officers are 30% higher

(Pxhere)
B.C. nurse suspended after using Tensor bandage to trap long-term care patient in room

Susan Malloch voluntarily agreed to a three-day suspension of her certificate of registration

Abbotsford’s Skully White (left), who donated his kidney in December, has started a campaign to find other recipients and donors. The first candidate is retired police officer Gavin Quon. White owns and operates a hotdog stand, Lullys Food Experience, out of the Abbotsford Canadian Tire parking lot. (Facebook photo)
After donating his kidney, Abbotsford hotdog king starts donor campaign

Skully White donated his kidney to customer Tim Hiscock in December

Toronto-based director Michelle Latimer was recently scrutinized after years of claiming she was of Algonquin and Metis descent. (CANADIAN PRESS/Chris Young)
Haida activist calls for hefty fines, jail time against those who claim to be Indigenous

Filmmaker Tamara Bell proposing the Indigenous Identity Act – to dissuade ‘Indigenous identity theft’

(File)
Man allegedly bites Vancouver cop during arrest for outstanding warrant

The officer was treated in hospital for the bite wounds

Black bear cubs Athena and Jordan look on from their enclosure at the North Island Wildlife Recovery Association in Errington, B.C., on July 8, 2015. Conservation Officer Bryce Casavant won the hearts of animal lovers when he opted not to shoot the baby bears in July after their mother was destroyed for repeatedly raiding homes near Port Hardy, B.C. THE CANADIAN PRESS/Chad Hipolito
Supreme Court quashes review of B.C. conservation officer who refused to euthanize bears

Bryce Casavant was dismissed from his job for choosing not to shoot the cubs in 2015

Most Read