April 24 to 30 is World Immunization Week, with the World Health Organization reporting that despite improvements around the world and a strong global rate of vaccination, current targets for disease elimination are behind schedule.
In May of 2012, 194 countries within the World Health Assembly signed onto the Global Vaccine Action Plan (GVAP), which set goals for preventing millions of deaths by 2020 through more equitable access to immunization worldwide and aims at the eradication of polio as a first milestone towards eliminating other vaccine-preventable diseases such as measles and rubella
“Immunization and vaccines are the most powerful public health tools that we have currently, “ says Dr. Flavia Bustreo, assistant director-general for the WHO’s Family, Women’s and Children’s Health Cluster, to Voice of America News.
The WHO reports that 35 years ago, 13 million children around the world died from vaccine-preventable diseases like diphtheria, tetanus, pertussis and measles. Today, that number sits at six million deaths per year, with 85 per cent of children now receiving immunization.
Through more concerted efforts, though, these deaths can be avoided by raising the overall vaccination rates, Bustreo says. “We need to have vaccination coverage that is about 90 percent, in order to have what we call the ‘herd effect,’” says Bustreo, “which means you cover the children who are vaccinated, but also, because of the reduction of transmission of infections, you also cover the children that are not vaccinated.”
Worldwide vaccination against polio and the real hope of completely eliminating the disease are seen as a clear success story for immunization. Polio mainly affects children under the age of five, with one in 200 cases of infection leading to irreversible paralysis and, in five to ten per cent of those paralyzed, death when breathing muscles become immobilized.
But efforts over the past three decades have paid huge dividends, with cases of polio dropping by over 99 per cent since 1988. In 2016, only 37 cases were documented, currently found in two conflict zones, in northern Nigeria and along the border between Pakistan and Afghanistan.
“The last part of eradicating any disease is always the hardest part,” says Dr. David Nabarro, a special envoy for the United Nations. “If you don’t do it, you lose everything. To do it, you’ve got to really bring all the energy and commitment you can to bear, and it requires a special kind of dedication.”
The WHO says that even in countries where vaccine-preventable diseases have become uncommon, the infectious agents that cause them can continue to circulate, and the highly interconnected nature of today’s global community means that anyone who is not vaccinated can get infected.
Recently, Canada’s interim chief medical officer of health, Dr. Theresa Tam, issued a statement calling on Canadians young and old to make sure that their measles vaccinations are up to date, especially for those planning to travel overseas this year. “In Europe, there are a number of countries experiencing cases,” said Tam to Global News.
Home-grown cases of measles in Canada were thought to be eliminated in 1997, but outbreaks still occur each year through unvaccinated or under-vaccinated Canadians coming into contact with infected people from other countries.
“The introduction can cause little sparks,” said Tam. “If you introduce that spark into a population that’s underimmunized, that actually catches fire. It will cause a cluster or an outbreak of cases.”