Jason M. Opal is a professor of history at McGill University, where he is teaching a class on the history of pandemics.
Children line up for a measles immunization in London, Ontario, in 1967. The vaccine was fired into the children's arms by an air gun. The measles vaccines are so good that they have made us forget how dangerous this virus can be. But if immunization rates continue to fall, this murderous pathogen could rage again.James Lewcun/The Globe and Mail
Ottawa health officials just reported another slump in childhood vaccinations against measles and now estimate that 15,000 kids in Canada’s capital are vulnerable to a disease that has been fully preventable since 1963. U.S. officials reported a similar drop in the wake of a recent outbreak in Ohio, which landed more than 30 children and infants in hospital.
No big deal, you say?
We rarely think of measles, and when we do, we tend to imagine it as a mere rash from olden times, a rite of passage for hardier generations. In fact, this virus was (and is) explosive and terrifying, killing about 2.6 million people each year in pre-vaccine times and probably contributing to many millions more over the centuries. Our forebears trembled at its approach.
On Oct. 18, 1713, for instance, the Reverend Cotton Mather reported “the Measles coming” to Boston, the old Puritan capital and the largest city in British North America. His son likely brought the virus into the Mather home that very day, endangering Mather’s pregnant wife, their maidservant and their nine other children.
Mather’s wife was stricken after delivering twins on Oct. 30. She had a splitting headache and a high fever along with the telltale rash. She couldn’t sleep. On Nov. 8, her husband gave a sermon about the Christian duty to accept the bitter cup that God sometimes offers. She died the next afternoon. “I cried to Heaven,” Mather wrote in his diary.
The scorching fever, the throbbing headache, the flat red spots over the face and chest – all of it swept through the Mather home like a prairie fire. We now know that the basic reproduction number of measles can reach 18 and that aerosolized virus particles can infect someone hours after a contagious person breathes them out. Like COVID-19, measles also spreads from presymptomatic people, making it almost impossible to control.
A week after his wife died, Mather watched his maidservant succumb. Within 24 hours, both of the newborns and his favourite, a toddler named Jerusha, fell sick. The twins died first, while Jerusha tossed and turned, drifting in and out of her waking nightmare. Around 10 p.m. on Nov. 21, she told her father that she “would go to Jesus Christ,” then was gone.
In all, 160 Bostonians died in the disaster, and many thousands fell seriously ill. Mather survived to become one of the earliest advocates for inoculation against smallpox, which he learned from a West African man named Onesimus.
What makes measles such a threat?
Usually, the fast-replicating virus presents as fever and rash and resolves within a week. But in some cases – the percentage varies widely and mysteriously – it involves the lungs, causing pneumonia, or the central nervous system, causing encephalitis. In small numbers of children, measles leads to subacute sclerosing panencephalitis (SSPE), a strange disorder that emerges seven years after the initial infection, causing seizures, coma and then death.
Two recent studies also found that a group of Dutch children whose parents shunned vaccination for religious reasons displayed a kind of “immune amnesia” for years after encountering this virus. Evidently, a measles infection wipes out huge repertoires of our antibodies and our B and T white blood cells, leaving us highly vulnerable to secondary infections.
So did Mather’s wife, maid, twins and daughter die of measles itself or of other infections they would have otherwise survived?
And what about the smallpox epidemics that devastated Indigenous communities from Brazil to British Columbia in a series of calamities between the 1500s and 1800s?
Measles, which was far more “catching” than smallpox, often preceded or accompanied these apocalyptic events. Perhaps the virus first wiped out immune systems, leaving people helpless against the slower but deadlier disease that followed.
Something similar may have occurred in the Hawaiian Islands after measles landed there for the first time in 1848. Once again, the virus raced through the population, intensifying the contemporaneous waves of respiratory disease and dysentery. One witness described whole villages struck down with measles; although most people survived the initial illness, huge numbers of infants in those communities died that year of whooping cough, a serious but usually not fatal disease.
The measles vaccines developed in the 1960s are so good that they have made us forget how dangerous this virus can be. But if immunization rates continue to fall, this murderous pathogen could rage again.
This nearly happened in 2019 in Vancouver, when a family with unvaccinated children brought the disease back from a trip to Vietnam. The virus quickly found the few vulnerable bloodstreams in two schools. In a less-immunized community, such as the ones that are now developing in Canada and the U.S., it could easily take off, endangering our kids and enfeebling our bodies’ defences against everything from influenza to COVID-19.
We’re all tired of viruses. We don’t want to argue any more about vaccines. We just want things to get back to normal, meaning the historically healthy “normal” we enjoyed after a wave of vaccines all but eliminated a range of diseases in the post-Second World War era.
That’s precisely why we need to remember what nano-level monsters such as measles can do, then act decisively to keep them in the past.