Thursday, June 25, 2009

Swine Flu (probably) Hits Leominster Schools

There's an interesting article in the S&E today about high absentee rates in Leominster schools. This is most likely an outbreak of swine flu/H1N1, but it seems as if those quoted in the article are reluctant to admit it.

Let's look at the article.
A large number of students have been out sick at Fall Brook Elementary School over the past week, but there have been no confirmed cases of swine flu, according to Superintendent of Schools Nadine Binkley.

"There has been a lot of flu going around, but it's of the fairly light variety," Binkley said.

Binkley said 65 students at Fall Brook were out sick Wednesday. The school has between 20 and 25 absences per day during an average week throughout the year, Binkley said.

Fall Brook has a total of 664 students.
Okay, that's a good chunk of students out. It's about 10% of the total student population, and three times the normal level.

There being "no confirmed cases of swine flu" doesn't actually mean a whole lot, because of the way the word "confirmed" is defined. According to the CDC, here's what it takes to be a confirmed case:
A confirmed case of novel influenza A (H1N1) virus infection is defined as a person with an influenza-like illness with laboratory confirmed novel influenza A (H1N1) virus infection by one or more of the following tests:

1. real-time RT-PCR
2. viral culture
So yeah, to be considered a "confirmed case," you have to actually do lab work to confirm it. You can have swine flu without being a confirmed case, and most people at this stage will not be confirmed cases simply because these tests are no longer being done for most cases.

This was pointed out in the article, though they neglect to give you the background about what "confirmed" means:
Leominster Health Director Christopher Knuth said Wednesday that there have been no confirmed cases of swine flu at Fall Brook, but also noted that the state recently stopped testing for it.

"We wouldn't get notified anymore," Knuth said.
Bingo. There actually can't be any confirmed cases if that testing isn't done. Hell, there probably can't even be any "probable" cases, since those also require a lesser degree of testing.

So when you read "but there have been no confirmed cases of swine flu", it really tells you nothing at all. These cases are going to be considered "suspected," as will the vast majority of swine flu. It's just not practical to test everybody at this stage.

Binkley's statement about there being a lot of cases of the flu going around, but them being "of the fairly light variety" is also telling.

First of all, there's no reason for that "but." H1N1 at this stage doesn't appear to be much more severe than the seasonal flu. Having had the seasonal flu, I'd never refer to it as "light," but if you're expecting H1N1 to be a death sentence you might.

Secondly, if there's a lot of flu going around currently, it's almost certainly H1N1. Here's a chart of flu cases by week from the CDC:

A very good explanation of this chart (including its weaknesses) can be found here, but I'll sum it up for you.

The orange bars represent swine flu, yellow is non-subtyped influenza A, which may or may not be swine flu, and the other colors are not swine flu, but are mostly what we'd consider the seasonal flu.

Knowing that, you can pretty easily see the seasonal flu fading away and the swine flu taking off. The little spike at the end of flu season is probably an artifact of increased testing as swine flu began to appear, but we were near the end of flu season, and subsequent weeks show it falling off.

The important thing to take from this is that the seasonal flu is basically done for this season. The swine flu is likely responsible for the vast majority of current flu cases.

Certainly it's possible that there are other factors at work in Leominster's situation. Absenteeism increases at the end of the year, normal colds and allergies may be getting misidentified as the flu, etc. But if it is indeed the flu, it's most likely the swine flu.

So, it's a possible flu outbreak. What are they going to do about it?
"We're going to sit tight with it for right now," Binkley said. "There are a lot of factors we weigh before we would close a school."

The Department of Elementary and Secondary Education advises schools to remain open as long as the absences have not affected teaching and learning, Binkley said.

"We don't have a high number of teachers out, and we feel that the classroom environment is still productive," Binkley said. "We don't think it's serious enough to close the school."
This is probably fine. There are indeed a lot of factors to consider before closing a school. A closure doesn't just affect the students, it affects the whole community. Sick kids means parents staying home to take care of them, which means those parents aren't at work, which means your plumber can't come fix that leak because he has to cover for his coworker whose kid is sick. The impact reaches a lot further than you might first imagine.

Since Leominster's last day before summer recess is tomorrow, it's probably more reasonable just to finish up the year than to close early and make a mess of things.

The article gives several good pieces of advice about what to do if you have the flu, most of which you've heard before. Most importantly, if you're sick, and especially if you have a fever, stay home.

Let me repeat that: stay home. That doesn't mean going to the grocery story instead of work or school. It doesn't mean hanging out with friends. It means sitting around in your house, feeling crappy. (If you want to kill time, I suggest playing this flash game about sneezing on people. It's oddly satisfying.)

When school gets out on Friday, any student who does have swine flu will suddenly have a lot more opportunities to infect others in the community. Even on vacation, staying home and not becoming a disease vector to those around you is important.

Finally, if you're healthy, don't worry. Yes, there is flu in the community. There's not much you can do about it outside of normal disease control measures (hand washing, careful with sneezing, etc). If you get it you'll probably feel pretty lousy, but unless you have underlying medical problems you're unlikely to die from it.

It's nothing to panic about, and it sounds like keeping the school open is a perfectly reasonable decision. But let's call a spade a spade. Yes, this is probably swine flu, and there's no reason to pretend otherwise. Now let's deal with it.