Recently, I booked a vacation to Sweden (the south). Because I was so happy to go there, I bought a few books about it. Then, I noticed that there is a chance that you can be bitten by mosquitoes and another bug (which I don't know the name of) that causes Lyme disease. To verify if that was true I went to my doctor and she adviced me to take three syringes. I was completly shocked. I'm not really a city tripper, but I want to discover Sweden's nature. Is there a big chance that you can get a bite?
Is Sweden full of mosquitos during the summer?
Full, no, but mosquitos are pretty much everywhere. The most recent ECDPC data indicate little to no invasive mosquito activity in Sweden so at least Zika is not a specific concern. Details at Mosquito Maps
Is there a big chance that you can get a bite?
The chances of getting bit by Ticks or anything in Sweden are not meaningfully higher or lower than anywhere else. You should apply the same precautions you would in any wooded area. Preventing Tick Bites
Don't worry and enjoy your holiday. I will!
Mosquitoes. Yes, Sweden can be full of mosquitoes, especially near still standing water such as a wet forest. However, the density strongly differs from one place to another and from one time to time. A little wind can make a huge difference. Some places are so full that the best is to keep moving, in other places one can have a pick-nick without any problem. If you want to avoid getting stung, use an insect repellant with DEET.
Midges The bite of these small flies differs from a mosquito because it hurts more. In general, these occur more locally, but if they occur then usually in large numbers.
Ticks Ticks are totally different from mosquitoes and midges because they are actually related to spiders. They can't fly and crawl up your shoes and pants to find your skin to bite. There they will stay for a few days to suck blood, unless you remove them. You should do this asap, because that decreases the chance of getting Lyme disease. An insect-repellant with DEET also works against thicks; there are even trousers and socks with DEET, this actually works very well in my experience.
I'm baffled by your doctor suggesting the three syringes, as there is no vaccine against Lyme. I think your doctor was thinking of tick-borne encephalitis, which requires three syringes. I find this rather far-fetched, but can't really advise you on this.
Source: I've travelled to Sweden a number of times and am actually going there this summer. I am also a European field biologist, and as such, belong to a risk category for Lyme disease (we get Lyme tests every year). And I do go into nature as much as I can and do not always stay on the track.