01:26 - Source: CNN
How vaccines stop the spread of viruses

Story highlights

World vaccination rates are healthy overall, according to the WHO

There was a 79% worldwide decrease in measles deaths between 2000 and 2015

Australia's "no jab, no pay" policy has spurred more than 200,000 families to action

CNN —  

A new policy in France requires all children born January 1 or later to receive 11 mandatory vaccines.

Vaccines against diphtheria, tetanus and poliomyelitis have always been mandatory in France, while eight – including whooping cough, hepatitis B, measles, mumps and rubella – had been recommended. As of New Year’s Day, the additional eight are mandatory.

Agnes Buzyn, France’s minster of health, said in a statement that the expansion to 11 compulsory vaccines represents 10 injections for children, spread over two years. Already, at least 70% of France’s children have been receiving all 10 injections, while 80% received more than eight, she said.

Why the change? Isabelle Jourdan, a spokeswoman for the ministry, explained that vaccination coverage in France is “not high enough” to meet the World Health Organization recommendation of at least 95%.

The ministry changed the policy to ensure that France will reach the goal.

“If parents refuse the mandatory vaccines, the main consequence will be that their children would not be accepted in schools, nurseries, etc.,” Jourdan wrote in an email.

Generally, Europe is experiencing a spread of measles due to “suboptimal” vaccine coverage, according to an October European Centre for Disease Prevention and Control report: From January 1, 2016 to June 30, 2017, there were more than 14,000 measles cases, causing 34 deaths.

France contributed 429 – or 3% – of these cases, but the majority of cases occurred in Italy (4,521, or 37%), Romania (4,276, or 35%), Germany (1,124, or 9%) and the United Kingdom (663, or 5%), according to the same report.

Immunity is a “game of numbers,” said Dr. Tim Lahey, a professor at the Dartmouth Institute for Health Policy and Clinical Practice, in which the “way to win is to get as many people as possible immunized so that it just disappears from the population.”

So how do governments encourage people to win the numbers game?

Human motivation is a tricky business. No one ever wants to be frightened into action, and even less do we want to be muscled into doing something – even if that something is the “right thing to do.”

Why governments encourage vaccination

Immunity from disease develops as a result of sickness or vaccines, which are killed or weakened versions of the disease that spur our immune systems to produce a defense against the real thing.

Yet there’s a hitch when it comes to vaccines.

“Most vaccines are partially protective but not fully protective,” Lahey said.

For this reason, if you look at some of US outbreaks of measles or mumps – which at least 90% of the population has been vaccinated against since 2000 – the people who get sick are usually those who have not been immunized. Still, even some people who have been vaccinated have become sick during an outbreak.

So if measles “immunization rates fall to, say, 50% to 60%, and we might say, ‘Heck, that’s not so bad,’ ” Lahey said, that still would mean that “probably 60% to 70% of people are vulnerable” to a life-threatening illness.

Medical experts say that between 92% and 95% of children should receive two doses of the measles, mumps and rubella (MMR) vaccine to maintain herd immunity, in which the entire group is protected because most individuals are. Even a highly infectious disease like measles simply cannot spread when herd immunity has been achieved.

But how do nations attain that high level? Naturally, the answers vary around the globe.


Though European vaccination rates are high overall, measles continues to spread where vaccination rates have declined, the World Health Organization warned in 2016. Measles is a viral disease that can lead to complications including pneumonia and encephalitis.

Eighteen countries – Austria, Belgium, Iceland, Luxembourg, the Netherlands, Spain and Sweden among them – reported more cases of measles during the first half of 2017 than during the same period in 2016, according to the European Centre for Disease Prevention and Control.

“Given the changing trends regarding increased vaccine hesitancy and refusal and consequent disease outbreaks, some countries such as Italy are introducing more mandates,” said Heidi Larson, an anthropologist and director of the Vaccine Confidence Project and associate professor at the London School of Hygiene & Tropical Medicine.

The majority of measles cases in Italy, 89%, were among unvaccinated people, and 6% of infections affected people who received only one dose of vaccine, according to a report from the European Centre for Disease Prevention and Control.

To address the spread of measles, Italy is essentially following the lead of the United States, which requires vaccination for school attendance. The Italian requirements, though, incorporate a few twists. Going forward, parents will provide proof of vaccination when enrolling their children in government-run nurseries or preschools, just as is done in the United States. But in Italy, the parents of children who have not been vaccinated will be fined. Conscientious objection, unlike in the United States, will not be allowed.

“Every European country is different,” Larson said. “Each have their own immunization schedule, which can differ between countries.”

Germany introduced legislation in June that made it mandatory for all kindergartens to notify the health authority if parents haven’t submitted proof of vaccination counseling for their children.

The policy marked a change to German law, which had required parents to submit proof that they have attended vaccination counseling before enrolling their children in kindergarten. This law, which had been in place for three years, didn’t require the school to report parents who have not been counseled by their doctors.

Generally, European nations tend to prefer voluntary vaccination to mandates, Larson said.

In 2015, Larson and her colleagues collaborated with WIN-Gallup International, which has conducted an annual survey since 1977, to look at vaccination attitudes across 67 countries. A total of 65,819 people were interviewed globally.

Though overall sentiment toward vaccinations is positive, the research team found wide variability between countries and across regions.

“Vaccine-safety related sentiment is particularly negative in the European region,” Larson and her colleagues noted in their report. “Countries with high levels of schooling and good access to health services are associated with lower rates of positive sentiment, pointing to an emerging inverse relationship between vaccine sentiments and socio-economic status.”

“I think the main point is that while there is overall good vaccine acceptance in Europe, there are clear trends reflecting more questioning about vaccines,” Larson said.

United States

All states use a requirement in which children cannot attend schools, including preschool programs, if their vaccinations are not up to date, though some states allow medical, religious and philosophic exemptions.

Typically, this school mandate “does increase the likelihood that children get immunized,” said Lahey, who sees the requirement not as a punishment but “as a carrot encouraging a carrot,” since both vaccination and school are positives people want for their children.

Yet some parents feel that their children ought to have the right to attend school “without accepting responsibility for the implications of doing that,” he said. Part of that responsibility is making sure school is a safe place. “And one way to make sure you’re safe is to not be contagious, and vaccines really help that,” Lahey said.

Still, he acknowledges that “sometimes in the conversation around vaccines, people can react against the incentive” and “develop resentments.” “They can feel like being encouraged to get immunizations gives them a loss of control,” he said. So while some parents opt out of vaccinating their kids, other people simply slip through the cracks.

Ultimately, then, there’s always a minority group that may not be vaccinated for one reason or another, Lahey said.

If this unvaccinated minority remains small, herd immunity can still be effective. A problem arises when the minority begins to grow.

Noel T. Brewer, a professor of health behavior at the Gillings School of Global Public Health at the University of North Carolina, sees people as falling into three camps.

There are those who understand and want vaccines and will go out of their way to get them, while in the opposite camp are those who do not want vaccines and “may even be activists,” he said. And then there’s the “great middle: that large number of parents who are not likely to take action one way or another unless someone prompts them to.”

Reaching those folks in the middle is key. So to increase vaccination rates, Brewer sees three possible approaches. “There are parents, there are providers, and then there are the systems, and we can try to address each of these in different ways.”

Yet directly reaching out to parents has not been “all that effective. So promotional campaigns don’t seem to do a lot,” Brewer said. Although social media seems to have a “fairly large influence” on what people talk about these days, “it’s unclear whether interventions through social media have much of an effect.”

According to Lahey, emerging data indicate that if someone in your social circle – whether that’s a person at your tennis club or your minister – puts vaccination forward as “a social norm, that does seem to encourage people to be more likely to get vaccination.”

Meanwhile, health care providers – whether doctors, nurses or physician assistants – are spending more time than in the past talking about this issue with patients, Brewer said.

“We don’t have evidence of that, but that’s what we hear,” he said. “The question is, how do we help physicians solve that?” From his research, the first step is clear.

“Most parents just want to know that (vaccination) is something a provider recommends,” Brewer said, explaining how he and his colleagues created “the announce approach, where physicians start off with just announcing a child is due – a presumptive announcement.”

Another piece is “a systems piece, and that could be everything from how the provider sets up appointments all the way up to the laws that govern vaccination,” Brewer said. In between are immunization information systems in every state that share information across providers.

At the systems level, though, there are problems, he said.

State immunization registries are often incomplete or have very out-of-date information, he said. So while it’s been shown effective to send reminder notices to parents based on data in the state registries, the record-keeping issues make this difficult. Also, some vaccines require parents to come back after six to 12 months, but appointment systems don’t go out that far.