5. Myth: Vaccinated children cause outbreaks
Also false. Immunisation currently saves between 2 to 3 million lives every year. However, there are rare instances when a disease may spread despite the population being vaccinated.
Some diseases change and evolve, which could impact the effectiveness of vaccines. The strain of bacteria or virus in the vaccine needs to be the same as the disease. That's why we are encouraged to have yearly flu shots – the flu virus can change rapidly.
But what about vaccine-derived outbreaks? Oral polio vaccine contains a tiny bit of weakened poliovirus that enables it to bring about an immune response in children and protect them from infection. But on rare occasions, as the vaccine-virus cycles through children’s bodies over time, it can mutate into a harmful form of poliovirus that causes paralysis and spread to those who are unvaccinated
If all children in the area are adequately immunised, this virus has no one to infect and dies away. The lower the population immunity, the longer these viruses survive.
This is what happened in both Yemen and Sudan in September 2020. Outbreaks of vaccine-derived polio were attributed to increasingly low levels of immunity among children. Both countries are facing conflict and restricted access, making it difficult to reach remote areas with life-saving vaccines for long periods of time. UNICEF teams continue to work day in, day out to reach every child, no matter their situation.
If a population is fully immunised against polio, it will be protected against the spread of both wild and vaccine derived strains of poliovirus.
That’s why we must continue this vital work to reach every child with regular immunisations and ensure that children and communities are protected from disease so that they can survive and thrive.
Now as the COVID-19 pandemic threatens the health of children and families, experts around the world are working hard to develop safe and effective vaccines.
As part of the Global COVAX Facility, UNICEF will lead the purchasing and delivery of vaccines to some of the world’s most vulnerable and remote countries.