In the US we have semi-compulsory vaccination. Keeping up to date on the vaccine schedule is required in order to attend public school. However, families always have the option of attending private schools, which can determine their own vaccination policy, or they can home-school. Also, each state can determine its own exemption policy. Medical exemptions are uncontroversial – if you medically cannot get a vaccine, that is up to your doctor, not the state. However, some states have religious or personal (philosophical) exemptions. These have been under increasing scrutiny recently.

Other countries have different systems. In the UK, for example, there is no compulsory vaccination to attend school.

These policies are all being reexamined in the wake of the burgeoning anti-vaccine movement and the resulting return of previously controlled vaccine-preventable illnesses. Let’s take measles, for example. As you can see by the chart, measles cases have increased by greater than 20 fold from 2010 to 2019 in the US. But if we pull back even further, in 1980 measles caused 2.6 million deaths worldwide, with cases in the US alone measured in the hundreds of thousands. By 2000 routine use of the MMR vaccine had prevented an estimated 80 million cases of measles.

Also by 2000 measles had been eliminated in the US – that means there was no circulating virus in the wild. All cases came from outside the country. Outbreaks were also very limited, because there was no fertile ground for the virus to spread. The antivaccine movement has changed that.

The rate of children getting MMR has not changed much in the US due to compulsory vaccines, ranging from 90-93% over the last two decades. It has dipped to around 91.1% recently, but the overall number remains high. However, this statistic hides what is really going on. Vaccine refusal clusters, by neighborhood and by school. If a private school does not require compulsory vaccination, then anti-vaxxers will cluster there. These pockets of very low vaccination rates then serve as potential locations for outbreaks, and that is exactly what happens. In recent years these outbreaks have been large enough to spread into the general population.

The UK, without compulsory vaccination, is in a worse situation. Their MMR compliance rate is around 87%. That may not seem like a big difference but it is. Around 95% is the percentage necessary to provide herd immunity, which is sufficient to stop the spread of any outbreak. The US is right at that level, but the UK is below it. That 5% drop makes all the difference. This is why the UK is considering adding compulsory vaccinations to public school attendance. We have a natural experiment between the US and the UK, and the US model just works better.

Europe generally is having a measles epidemic, with 82,500 cases in 2018. Here is a list of vaccination policy by country. As you can see, very few have mandatory vaccines with proof of compliance to attend school. Given the extent of international travel, as the European experience shows, the spread of vaccine preventable diseases is really an international problem.

So – what’s all this leading up to? I think we have a strong case for compulsory vaccines, that these laws should be strong, and there should be international pressure for all nations to have some reasonable requirements. That pressure could involve requiring proof of vaccination before being allowed to enter one’s own country.

The ethical justification for this, I think, is pretty solid.  There is often a conflict between individual liberty and the interests of the state, which may reflect the collective interests of our fellow citizens. Speed limit laws are a good example of this. We restrict the rights of individuals to drive as fast as they want, because they are not only taking their own life into their hands, they are affecting the risk of everyone sharing the roads with them. These are public roads, paid for and maintained by public funds. Scientists can also look at data and inform policy regarding the risk vs benefit of different speed limits.

Further, if you do get into an accident, even only involving yourself, emergency services will respond at great public expense. Resulting health care expenses may also be a burden on the system, even if you have good insurance the expense raises the cost of health care overall, which is ultimately covered by everyone else. So to some extent we are all in this together, which means we can have common rules we all follow. We don’t allow individuals to decide for themselves what the optimal speed limit is. We use an objective, reviewed, and transparent metric.

The general ethical rule is that – if society has a genuine interest, which is informed by objective data, then individual liberty can be limited to meet this interest, as long as it is reasonable and in proportion to the benefit. In the US, where we appropriately value liberty (in my biased American opinion), the state has the burden of proving their case, with liberty being the default position.

I think all this applies to vaccination. We are all in this together, we all collectively bear the cost and risk of disease. The choices that other people make affect all of us. In the case of vaccines, this is also an issue heavily informed by science. The scientific community has spoken, with decades of careful evidence. Vaccines are generally safe and effective. They are the most effective and cost effective public health measure ever developed. They work, they save lives, they save money, and they present minimal risk (although non-zero – there is never zero risk).

There is no genuine scientific controversy regarding the vaccine schedule. I think we have an extremely strong case for compulsory vaccines – which are a benefit to the individual as well as the community. People who oppose vaccines are objectively wrong. They are citing bad or disproven science, conspiracy theories, and pseudoscience. I do not think they should have the right to replace a strong scientific consensus with their own personal opinion, and in so doing put other people at risk and cost society resources.

We also know that compulsory vaccination works. Further, the more limited exemptions are, and the harder to obtain, the higher the vaccination rate. Every state should eliminate all non-medical exemptions for vaccines.  I would go further – I would deny charters and certification to private schools that do not require vaccination. Otherwise we are just forcing unvaccinated kids into close quarters, creating the conditions for outbreaks. If you want to fully avoid vaccines, you will have to home school.

We will never eliminate the anti-vaccine movement, but we don’t have to. We just have to marginalize it sufficiently that we can get to the 95% community immunity level we need. We are close, but not close enough. The one easy thing in all this – it’s really easy to tell how a policy is working. All we have to do is track disease statistics, which we already do. The numbers will tell the story. They are telling the story. Compulsory vaccination works. It’s good, and ethically defensible, policy.