Personally, I'm disgusted with the two-party system and don't belong to either party. I form my own subtle views on an issue-by-issue basis, and feel no need to identify with one of two groups and let that affiliation decide my opinion on everything.
When considering who is generally intelligent and "pro-science", I think there are two general types. If you are the intellectual type who thinks for the sake of thinking and spends time contemplating where humanity is going to be in 100 years, 1,000 years, and 10,000 years, you are probably going to lean left. But if you are the here-and-now business type with a much shorter horizon, you are going to want to minimize interference in your business and minimize the taxes you pay. That type of person will of course lean right.
If those groups are the real intellectual drivers behind the political parties, then it makes sense that since both types of people are small minorities, they need to form alliances with larger groups. The left has formed alliances with union workers, minorities, women groups, pseudo-intellectuals, new agers, and neo-hippies. The right has formed alliances with gun nuts, evangelical Christians, Pentecostals, Mormons, militias, and neo-Nazis.
Both sides have sold out to the military-industrial complex.
That's the way I see it, at least.
Regarding vaccines, it's worth pointing out that
Donald Henderson,
Bill Gates, and Warren Buffett are all democrats (or in the case of Bill Gates at least, clearly leans left).