Anti-vaxxers 'are a threat to those with poor immune systems'
When there are outbreaks of measles, mumps and even strains of the flu, Johannesburg mother Kyara Bergstrom sits with "so much fear and anger", praying that her daughter will be safe.
That's because Isabella, 13, needs other children and adults to be vaccinated to keep her, and others like her, alive.
She can't fight infections on her own as she has a T-cell defect as well as a mannose-binding lectin deficiency.
Isabella relies on immunoglobulins and goes to a school that requires completed vaccination cards upon enrolment.
"I try to avoid anyone that I know isn't vaccinated, including people close to me that I know haven't vaccinated their kids. It's not worth putting Izzy at risk.
"But the problem comes in just with going to school and being in public - you don't know if people have been vaccinated or if they are infected," said Bergstrom.
The growing anti-vaccination movement on social media and vaccine hesitancy are putting millions of children's lives at risk.
The World Health Organisation lists vaccine hesitancy as a threat to global health.
"Vaccine hesitancy - the reluctance or refusal to vaccinate despite the availability of vaccines - threatens to reverse progress made in tackling vaccine-preventable diseases," the organisation said.
Governments around the world are clamping down on anti-vaxxers, whose opposition stems from a discredited study that claimed to have found a link between autism and the vaccine for measles, mumps and rubella (MMR).
Italy has banned unvaccinated children from attending school, and the mayor of New York this week ordered that all residents be vaccinated to contain a measles outbreak in Brooklyn.
South African health authorities this week told the Sunday Times that although there was vaccine hesitancy on social media, most South African communities were firm believers in vaccinations.
However, Durban mother Nikkita Cilliers is not one.
Cilliers believes that her now four-year-old daughter's walking and talking were delayed due to the nine-month vaccination.
Her "personal experience" stopped her from vaccinating her children, but Cilliers admitted that "the stories on social media of people going through the same thing sealed the deal for me".
The spokesperson of the department of health, Popo Maja, said its personnel often had to debunk myths about vaccinations due to the negative messages posted online by anti-vaxxers.
The South African Vaccination and Immunisation Centre found that about 20% of South African posts were negative towards vaccinations from 2016 to 2017.
However, the centre's professors Rose Burnett and Hannelie Meyer said calling "this an anti-vaccine movement would be an overstatement as there doesn't seem to be a well-organised and cohesive movement".
The centre receives about 10 calls from parents, mostly pro-vaccine, each month.
"Since December 2016, we have received only two calls from parents who were particularly concerned about stories that the MMR [vaccine] causes autism," said the centre's health programme coordinator, Varsetile Nkwinika.
The head of the vaccines and immunology centre at the National Institute for Communicable Diseases, Dr Melinda Suchard, said there was a difference between "vaccine refusal" and "vaccine hesitancy".
"Mostly we see vaccine hesitancy, where people are seeking reliable information in order to make informed choices. There is, unfortunately, a lot of misinformation available on the internet and social media.
"It is difficult for the public to distinguish between reliable information from trusted organisations and the personal opinions of individuals blogging, some of whom invent fake 'organisations' and websites with official-sounding names."
She believes children are often not vaccinated in SA simply because their parents forget to go back for the later vaccines.
"Mothers are very good at going for the six-, 10- and 14-week immunisations but forget to get the later vaccinations, which include measles. Children require vaccinations until 18 months of age, and again before primary school and high school.
"Mothers should be reassured that if any vaccines have been missed, it is never too late to catch up," said Suchard.
Vaccine cover (percentage of SA children vaccinated):
2014/15 - 89.9%
2015/16 - 89.2%
2016/17 - 71.2%
2017/18 - 77%..