Amanda Ripley Author of The Unthinkable

The single biggest challenge (so far) about swine flu is that the two questions your brain most badly wants answered are technically unanswerable: 1. What are my chances of getting it? 2. What are my chances of dying?

Our brains are wired to ask those questions. They are damn good questions. But no one really knows the answer (more on why that is coming soon). In the meantime, the trick is to make an educated guess. And that we can do pretty easily.

A bunch of people have emailed me lately to ask for help with the educated guess. I’m no doctor, but I’ve been fairly well immersed in studying swine flu (formally known as pandemic H1N1 of 2009) for a couple months now, as those of you following me on Twitter know a little too well. And I know a bit about how the brain processes risk—and the mistakes we tend to make. So here’s what I think:

1. Should I get the regular seasonal flu shot?

I would. It will be available earlier than usual this year, and even though it offers no protection against swine flu, it is a good way to hedge your bets. Why? Well, swine flu (the other flu) is extremely infectious—so your chances of getting it may be relatively high. If you get it,  you will almost certainly recover. It is milder than regular seasonal flu so far. But it will kind of suck to be sick as a dog for a week to 10 days. If you get the seasonal flu shot, you at least reduce your chances of being sick as a dog twice this year. Plus, the truth is, too many people die or get hospitalized from seasonal flu in an ordinary year. So might as well not be one of them.

And let’s be clear: there’s no evidence that you can get the flu from the flu shot. The shot contains a killed, inactive version of the virus. The flu mist nasal spray contains a live version, but it is very weak. You may get a low-grade fever for a day or two, if you’re unlucky, but nothing like the actual flu. This thing is pretty well studied at this point, and it is very safe. I plan to get it, as I usually do. I figure my life is frantic enough without getting knocked flat by an optional virus.

2. Should I get the H1N1 (swine flu) vaccine when it comes out later this fall?

I will be getting it. I am not a health care worker or pregnant, under age 25, diabetic, asthmatic or dealing with any of the other chronic conditions that put people at higher risk. So I don’t want to take someone else’s dose. But once it’s widely available, which will probably be in November or so, I plan to get it.

It’s being manufactured the same way the regular seasonal flu vaccine is manufactured. Every year, the flu vaccine is altered to address different strains. So this is the same deal: same vaccine shell for a different strain. Also, it is being tested all summer by regular (if weirdly generous) people, and that includes pregnant women, small children and the elderly.

3. What about my kids? Should I get the vaccines for them, too?

This one is the easiest question, actually. Children are at higher risk when it comes to both kinds of flu (swine and seasonal). So as long as they are over 6 mos old and don’t have a severe allergy to chicken eggs, it makes sense to get them vaccinated for both. If they have any underlying issues—like diabetes or asthma—it is even more urgent.

OK, take a deep breath: For some kids, this may mean getting 4 different doses in all… Kids need two shots of regular flu vaccine the first year they get the shot (and only one seasonal flu shot after that)—and may need two shots of the new, H1N1 vaccine, too. This sounds unreasonable, I know. But it will probably be easier than ever to get these shots this year. Lots of schools, stores, pharmacies and doctor’s offices will be offering them. Also, the feds are paying for the H1N1 vaccine, so you should only have to pay a small administrative fee (or nothing, if your insurance covers it).

Lots of people are worried about thimerosal (a preservative) in vaccines. I’m not going to get in the weeds here on this very passionate debate, but I will say that both vaccines will be offered to children in thimerosal-free versions. So hopefully this won’t be a big issue. If you want to know more about the thimerosal debate, I recommend How Safe are Vaccines? by my Time colleague Alice Park.

For anyone trying to convince someone else (say a spouse or a grandparent) that the flu shot is a good idea for a child, you could always have them watch this CDC video. Once you’ve seen it, it’s hard to forget… And I know it’s kind of a cheap shot, because stories are always more compelling than stats (and the fact is that the number of kids who die from flu each year is pretty small—compared to, say, the four kids who die every day in car crashes in the U.S.). But still. There is a time and a place for manipulative storytelling, and this may not be a bad time and place:

4. What if I’m pregnant? Or thinking about getting pregnant?

So far, pregnant women have represented 6% of the people who have died from pandemic H1N1, according to the CDC. Pregnant women have also represented 6% of those hospitalized with the virus. But pregnant women only actually represent 1% of the population. So you can see that they are at higher risk of having serious issues from this otherwise moderate bug.

That said, if you are pregnant, your chances of having problems are still pretty small. If I were pregnant, I would get the vaccine as soon as it becomes available (likely mid-October). As I mentioned, it is being tested on pregnant women right now. And it is almost identical to the regular seasonal flu vaccine, which pregnant women are also supposed to get.

It’s hard to say if there’s enough risk to delay getting pregnant until the vaccine comes out… But since it’s coming out in a month, maybe it’s not such a hard question. Still, keep in mind that it will take 3 weeks for you to develop immunity—starting from the day you get your shot. Why? Because it takes a few weeks for your body to develop immunity.

5. So what’s the big deal?

Flu viruses are crafty bastards. They can change at any time. So the best defense is wisdom. You don’t need to worry about it as long as you check in with a few different, reliable sources of information every so often. What is a reliable source when it comes to swine flu? I can tell you that it’s generally not TV news. This thing is too nuanced for segments that last 52 seconds. But pick a couple sources—ideally ones that don’t all link to each other. My own favorites:

FLU.GOV (the federal government’s site)
FLUWIKI (a collaborative problem-solving wiki site)
THE PETER M. SANDMAN RISK COMMUNICATION SITE (a great site by an expert in risk communication—who has been following H1N1 closer than 99% of the population. Also, he’s funny, honest and blunt.)