During my immersion in the skeptic movement, I have come across some silly ideas. For instance, some folks have espoused for a flat Earth, or for Earth being round but hollow and inhabited by benevolent creatures trying to telepathically communicate with us.

Others ideas are potentially harmful, depending on what the person wishes to do with their beliefs. For instance, someone on an anti-GMO rant is relatively innocuous unless they want the government to ban golden rice, a Vitamin A-rich food that prevents blindness in poverty-stricken countries. Or a person who posts a meme purporting to show that the Big Bang is a myth is hurting no one, unless he lobbies to make this a staple of public school astronomy classes.

But the most dangerous I’ve encountered, by far, are the anti-vaxxers, whose actions threaten those too young or unhealthy to be given immunizations. Here are 10 frequent arguments I hear from anti-vaxxers put forth, and my counters to them.

1. “Vaccines are not guaranteed to be safe.” And neither is polio. Some vaccines have mild side effects, and there is the very rare serious complication. All that is explained here. If safety is the overriding concern, vaccines are the way to go.

2. “Vaccines are not guaranteed to be effective.” Nor are parachutes, but skydivers are much better off percentagewise in using them. And failing to vaccinate is zero percent effective at preventing disease. Vaccines have greatly reduced the instances of some diseases and have eradicated others. That there is an infrequent person they won’t work for is not a sound reason for someone else bypassing them.

3. “Death rates were already declining and the introduction of vaccines was incidental to this trend continuing.” It’s true that death rates were declining, but infection rates were steady or increasing. Disease rates drop dramatically when vaccines are introduced, and skyrocket when people stop getting inoculated. One anti-vax graph showed how death rates had dropped to one-thirteenth their previous rate before the measles vaccine was introduced. A pro-vaxxer then added the pertinent information that the measles infection rate went from 275 per 100,000 to zero within five years of the vaccine being introduced.

4. “The polio vaccine of the 1950’s was contaminated by the SV40 virus which is now confirmed to have caused cancer in many people who had received the vaccine. It’s a matter of Russian roulette on when such a virus will sneak into another vaccine.” This is the argument from ignorance and provides no evidence that any current vaccine is dangerous. Again, if safety is the concern, get your shots. This argument also glosses over scientific improvements in the last 60 years that make this kind of mistake less likely today.

5. “Cow cells, monkey cells and chick embryo cells are all found in various vaccines. How can anyone really know the long term effects of injecting this foreign DNA into a six-week old baby’s body?” The second sentence comprises two logical fallacies, the appeal to emotion and the argument from ignorance. Additionally, the first sentence is wrong, as none of those animal cells are in vaccines, although the vaccines may contain cell proteins. Moreover, there is nothing to suggest those cell proteins are dangerous.

6. Continuing our field trip to the Fear Factory, we are told, “Add some heavy metals, antibiotics and preservatives, and you have a toxic cocktail called a vaccine.” This plays to some people’s lack of chemistry background. Some folks pump a mix of zinc, coal tar extract, and polysorbate 20 into their arms. It’s called insulin. Likewise, sodium will explode in water and chlorine is a poison gas weapon, yet together they make table salt and give us yummier French Fries. Danger is determined by dosage, not chemical or element.

7. “Big Pharma cannot be trusted and is in it for the money.” Which is irrelevant to whether vaccines work. One need not trust a company to believe in the science behind its products.

8. “Herd immunity is a myth.” I’ve never seen this one followed up with any numbers or supporting arguments of any kind. Anti-vaxxers seem to be just throwing it out and hoping it will stick with somebody. Herd immunity is real and it is what happens a virus has difficulty spreading since enough of a population is immunized. This is especially important for those too young or unhealthy to be immunized.

9. “In New Zealand, 65 percent of people who contracted whooping cough in 2012 were vaccinated.” Taken by itself, this statement is true, and indeed, vaccines will not always prove effective. What this statistic left out however, was that nine percent of those vaccinated got the disease, compared to 45 percent of those who were unvaccinated.

10. “Diseases are actually caused by vaccines, so the vaccinated are a threat to the unvaccinated because they shed disease.” What’s being shed is the inactivated virus, so there is no danger to anyone, except in the very specific (and revolting) instance of an immunocompromised person coming into contact with the excrement of a recently vaccinated individual. And even if the vaccinated made the unvaccinated sick, I’ve learned from my chats with naturopaths that there’s no ailment beyond the scope of ­­Reiki and peppermint oil.