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.

Just Posted

RDEK is calling for nominations for their Volunteer of the Year award in all six electoral districts.
RDEK posts operating surplus as pandemic reduces costs

The RDEK has posted a operational surplus of $8 million as local… Continue reading

North Okanagan business Hytec Kohler set up a COVID-19 vaccination clinic at the Spallumcheen plant Friday, May 14. (Jennifer Smith - Morning Star)
More than half of eligible adults in Interior Health vaccinated

Over 365,000 vaccine doses have been administered throughout the Interior Health region

Fernie Ghostriders head coach Jeff Wagner has committed to two more years with the team. Phil McLachlan/The Free Press
Fernie Ghostriders coach departs: Wagner moves to Coquitlam

Jeff Wagner will move to the Lower Mainland as associate coach and director of scouting with the Coquitlam Express

New Border Bruins owner Dr. Mark Szynkaruk reps team colours with his young sons and wife Tracey. Photo courtesy of the Grand Forks Border Bruins
KIJHL’s Border Bruins sold to Grand Forks doctor

The league announced the sale Friday, May 14

Daily confirmed COVID-19 cases reported to B.C. public health, seven-day rolling average in white, to May 12, 2021. (B.C. Centre for Disease Control)
B.C. preparing ‘Restart 2.0’ from COVID-19 as June approaches

Daily infections fall below 500 Friday, down to 387 in hospital

Poached trees that were taken recently on Vancouver Island in the Mount Prevost area near Cowichan, B.C. are shown on Sunday, May 10, 2021. Big trees, small trees, dead trees, softwoods and hardwoods have all become valuable targets of tree poachers in British Columbia as timber prices hit record levels. THE CANADIAN PRESS/Jen Osborne.
Tree poaching from public forests increasing in B.C. as lumber hits record prices

Prices for B.C. softwood lumber reached $1,600 for 1,000 board feet compared with about $300 a year ago

The warm weather means time for a camping trip, or at least an excursion into nature. How much do you know about camps and camping-related facts? (John Arendt - Summerland Review)
QUIZ: Are you ready to go camping?

How many camp and camping-related questions can you answer?

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

On Friday, May 14 at Meadow Gardens Golf Club in Pitt Meadows, Michael Caan joined a very elite club of golfers who have shot under 60 (Instagram)
Crowds at English Bay were blasted with a large beam of light from an RCMP Air-1 helicopter on Friday, May 14. THE CANADIAN PRESS/Marc Grandmaison
Police enlist RCMP helicopter to disperse thousands crowded on Vancouver beach

On Friday night, police were witness to ‘several thousand people staying well into the evening’

People shop in Chinatown in Vancouver on Friday, February 5, 2021. THE CANADIAN PRESS/Jonathan Hayward
Vancouver community leaders call for action following 717% rise in anti-Asian hate crimes

‘The alarming rise of anti-Asian hate in Canada and south of the border shows Asians have not been fully accepted in North America,’ says Carol Lee

Sinikka Gay Elliott was reported missing on Salt Spring Island on Wednesday, May 12. (Courtesty Salt Spring RCMP)
Body of UBC professor found on Salt Spring Island, no foul play suspected

Sinikka Elliott taught sociology at the university

The first Black judge named to the BC Supreme Court, Selwyn Romilly, was handcuffed at 9:15 a.m. May 14 while walking along the seawall. (YouTube/Screen grab)
Police apologize after wrongly arresting B.C.’s first Black Supreme Court Justice

At 81 years old, the retired judge was handcuffed in public while out for a walk Friday morning

Most Read