Outbreak of measles in Denmark

Yesterday the Danish Board of Health issued a warning about a relatively large outbreak of Measles in Denmark (some of the links in this post may be in Danish).
So far 6 people have been diagnosed during the last two weeks and compared to last year with only 5 measles incidents in total, this is huge. And it could potentially lead to more cases if an infected person has managed to evade quarantine (inadvertently).
The infected persons are primarily unvaccinated young adults.

The measles may not immediately cause a concern as it is most often not fatal, but it can be fatal and globally it is a great concern. And unless we take measures to stay protected it may become a problem here as well.

Cause
So far I have no idea what caused this but there seems to be a decline in vaccination levels in Denmark and the current levels of vaccination of the MMR vaccine is around 85% (it's called MFR in Danish).
Why this is, I don't know, but a lot of scary, uninformed and malicious people have been propagating the lie that the MMR vaccine may be a cause of autism. This is wrong, the MMR vaccine does NOT cause autism. But the scaremongering has caused a drop in vaccination levels as parents become afraid.

So unless there is a medical reason (allergies, immune deficiencies, other illnesses) make sure your children are vaccinated. If you haven't been vaccinated yourself (and you've never had the measles) go see your doctor and get the shot.

Why vaccinate?
To protect yourself, your children and everyone around you.
Vaccinations will allow your immune system to more effectively protect against the virus and give you a high (95% or so) chance to resist infection.
Because the protection isn't 100% certain and because some people cannot get the vaccination for medical reasons, it is so much more important that those who can get it, do so.

This is because of an effect called 'herd immunity' which is just that. Through high rates of vaccinations throughout the community (or herd) the entire herd becomes immune as there are no places for the virus to gain a foothold.
Even if someone becomes infected the virus is unable to spread throughout the herd, protecting even those who aren't immune.
If more people decide against vaccinations the herd immunity breaks down. Generally anywhere between 80-90% vaccination coverage is enough. But as the average vaccination rate drops, local pockets of entirely unvaccinated subgroups emerge. And in these groups it is possible for the virus to gain a strong presence and eventually begin infecting even the vaccinated areas.

Herd immunity is important for our survival and vaccinations is the way to obtain it.
Through vaccinations the WHO has reduced the global death toll from measles from more than 750.000 to less than 200.000 in just seven years.