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

Kootenay-Columbia MP Rob Morrison speaks during Question Period in the House of Commons. File photo.
MP Morrison calls Keystone XL permit cancellation ‘devastating news’

Kootenay-Columbia MP reacts to the Conservative Party’s removal of a controversial Ontario MP

Interior Health reported 91 new COVID-19 cases in the region Jan. 20, 2021 and three additional deaths. (Jennifer Smith - Morning Star)
95 new COVID-19 cases in Interior Health, two deaths

Another member of Vernon’s Noric House has passed

The Greater Vernon Ringette Association is one of six Vernon sports groups benefitting from B.C.’s Local Sport Relief Fund. (Morning Star file photo)
Relief funds keep Okanagan in the game

Clubs at risk of closure due to inability to offer programs and fundraise

Golden Rotary Club president Isabelle Simard presents a check in Invermere to the winner of Golden’s bingo. (Michele LaPointe photo)
Golden Bingo continues to grow; expands to other BC communities

The money is going back into the community through various Rotary projects

Toronto Public Health nurse Lalaine Agarin sets up for mass vaccination clinic in Toronto, Jan. 17, 2021. B.C. is set to to begin its large-scale immunization program for the general public starting in April. THE CANADIAN PRESS/Frank Gunn
B.C.’s COVID-19 mass vaccinations expected to start in April

Clinics to immunize four million people by September

Clint George collaborated with Les Louis to create the Pelmewash Parkway Indigenous sculptures in Lake Country. (Video still)
First Indigenous territory recognition made in Lake Country

Council makes historic move after Syilx artists create parkway sculptures

Police are searching for an alleged sex offender, Nicole Edwards, who they say has not returned to her Vancouver halfway house. (Police handout)
Police hunt for woman charged in ‘horrific’ assault who failed to return to Surrey halfway house

Call 911 immediately if you see alleged sex offender Nicole Edwards, police say

A screenshot from a local Instagram account video. The account appeared to be frequented by Mission students, and showed violent videos of students assaulting and bullying other students.
Parents, former students describe ‘culture of bullying’ in Mission school district

Nearly two dozen voices come forward speaking of abuse haunting the hallways in Mission, B.C.

Vaccine rollout is focused on health care workers first, especially those dealing with long-term care facilities. (Nathan Denette - Canadian Press)
General public shouldn’t expect vaccines until fall: Interior Health South Okanagan Similkameen

Interior Health focused on vaccinating long-term and first-line care workers

Joe Biden, then the U.S. vice-president, and Prime Minister Justin Trudeau take their seats at the start of the First Ministers and National Indigenous Leaders meeting in Ottawa, Friday, Dec. 9, 2016. THE CANADIAN PRESS/Adrian Wyld
Trudeau, Biden to talk today as death of Keystone XL reverberates in Canada

President Joe Biden opposed the Keystone XL expansion as vice-president under Barack Obama

Prince Edward Island’s provincial flag flies on a flag pole in Ottawa, Friday July 3, 2020. A lozenge plant in Prince Edward Island has laid off 30 workers, citing an “almost non-existent” cold and cough season amid COVID-19 restrictions. THE CANADIAN PRESS/Adrian Wyld
‘Almost non-existent’ cold and cough season: P.E.I. lozenge plant lays off 30 workers

The apparent drop in winter colds across the country seems to have weakened demand for medicine and natural remedies

Authorities have confirmed a case of COVID-19 within a school in Kelowna. Someone within the Rutland Elementary School community has tested positive. (Aman Parhar/Omineca Express/FILE)
Authorities confirm COVID-19 exposure in Central Okanagan school

Interior Health (IH) states they will be following up with anyone potentially exposed

Homeless man lying on the bench. (File photo)
Temporary emergency shelter opens in Central Okanagan

The shelter, located at the former location of Tree Brewing, will offer 38 beds

Most Read