I’ve been searching daily for interesting articles in the
primary literature and posting them on FB with short summaries, but I haven’t really
given much of my personal sense of the current gravity of the situation. When I started grad school, we were all put
in a room and taught how to read a scientific paper. You should focus on the methods (what the
researchers did) and the results (what they saw happen), but come up with your
own conclusions before reading the discussion section, where the authors give
their conclusions and interpretation of the data. In fact, you might even consider skipping the
discussion section altogether. So my
instinct is to show people data and let them draw their own conclusions. But sometimes discussion sections can be
really helpful. The authors have more
experience with their system, and may well have thought of something I haven’t.
So while I still like the data-focused approach, I can see the value of a periodic
“discussion section” to my blog / FB wall to give people a sense of what I
think the data mean.
I first became aware that there was a coronavirus outbreak
in China shortly after Christmas. The
CDC website had a page on it, and I was looking at their viral surveillance
section to try to figure out what the crud that was going around was caused by
(that disease was clearly not covid. It
didn’t kill enough people). At that
point, I was thinking of this new coronavirus as another SARS or MERS -- sad in that it was killing people far away,
but unlikely to spread through the whole world. But by early March it was
clearly starting to spread, and by March 11, it was declared a pandemic, which
means that it was spreading quickly through many different countries. The thing that apparently makes this virus
more prone to becoming a pandemic than SARS or MERS is that it can be spread by
people with no symptoms at all. With
SARS, you could take someone’s temperature before they got on a plane and have
a pretty good idea whether or not they were shedding virus. But this new virus is being spread by people
in the 5-day incubation period, and by some people who never have symptoms. I took that as a sign that this could be "the big one," which I always assumed would be flu, but life is full of surprises.
By March 15th, I was wearing a mask when I went
out in public. I was the only
one. I was sanitizing my hands with alcohol, and wiping down all the packages
that I brought into my house. I was
avoiding going out as much as possible. I’m not a paranoid person, and definitely not
a germophobe. I knew that as a healthy
middle-aged person, I was very unlikely to die of the virus, and because I work
alone at home, I’m unlikely to pass it to anyone else if I did catch it. But I don’t really have health
insurance. I have a health sharing plan
with a very high deductible. And I know
our broken health care system could result in medical bills that might not be covered and could ruin me financially. People who land in the hospital with covid stay there for 1-3
weeks. That is not a small medical
expense. I had planned to move to France
in December of this year, and France has an excellent and inexpensive health
care system. My plan was to not get sick
or injured before then. I’m still not
entirely sure what my chances of being hospitalized would be if I caught the
virus. But I don’t think the CDC estimates
of 20% are crazy. Beyond the cost, there are also many people who survive but have a long road to recovery. People are having strokes and heart attacks because of the virus. Being on a respirator for weeks can permanently damage your lungs. So I am highly motivated
to avoid catching this virus.
I’ve known since the beginning that the quarantine by itself
was not going to prevent infections and save lives. What the quarantine gives us is time to study
the situation and figure out some way to deal with it. It doesn’t look like we’ve come up with a
wonder drug, and we still don’t know why some areas are harder hit than
others. But there has been a lot of
progress toward a vaccine, and one group in the UK has announced that they
expect to have their first million doses available by the fall, and they will
know for sure if they’re on the right track by June. At this point, I’m confident that there will
be a vaccine that works well enough to stop the virus, and once we’ve gotten it
and waited the six weeks (ish) it takes for it to activate the immune system,
we can get back to normal.
In the meantime, we have also learned that masks work really
well in preventing infections. Back in
mid-March, I was wearing my N95 mask, but I wasn’t entirely confident that it
would protect me, and now I am. They’re
not comfortable, but they work. If masks were 100% effective, we would need about 60% of people to wear them to prevent exponential growth of the virus. I would link to all the studies here, but I think masks need their own post, so I'll link to it once I'm done. Update: link here.
Another happy discovery is that sunlight kills the virus within minutes. So in the time it takes
me to roll my cart full of groceries to my car, unload them into the car, and
put the cart where it belongs, I’m exposed to enough sunlight that I’m not
worried about virus clinging to my clothes or hair and coming home with me. I still alcohol my hands, because I can
imagine that my palms don’t get enough sun to kill the virus, and hands are a
major source of transmission of viruses in general. But I’m not worried that I’ve contaminated
myself by going to the grocery store.
If you look at various studies that track R0, you see a
pattern happening over and over again.
The R0 is high at first, for example this study estimates 4.5, then it comes down to the 2-3 range. This suggests to me that a big part of
transmission is the sort of thing that was easy to change. People were shaking hands with someone who
probably didn’t wash their hands after using the bathroom, and then rubbing
their eyes. Once the first wave of sick
people showed up, everyone started being more careful, even as they went about
their normal lives of school and work. This helped a lot. By March 15th, which is the point where I was aware that I needed to be careful, the R0 for most of the US was already down to 1.5 or so. Then we went into quarantine, and the R0 went
down even more. You can see graphs of R0 over time for US states here. The large majority of states are currently in negative growth of the virus. (Side note: this website uses the term Rt instead of R0. There seems to be disagreement between epidemiologists about whether R0 should be reserved for the "background" level of spread without taking measures like we are now. The thing is, it's almost impossible to define what behavior counts as background, so I just use R0 to mean whatever the reproduction rate of the virus is at a given point.)
So the
question now is, how much can we open up while still keeping the spread rate
negative? We are clearly being more cautious now in TN than before the quarantine
began. I see about three-quarters of
people wearing masks in the grocery store, and before the quarantine, it was none.
We don’t really know at this point whether or not eating in
a restaurant with six feet of space between tables will lead mass outbreaks,
but apparently we Tennesseans (and several other states) are going to do that
experiment. There was one instance of
spread in a restaurant in China, apparently due to air flow over much longer
distances. I most definitely will not be
eating out in the near future. I’m hoping that the people
who do are young and have good health insurance.
I was encouraged by this study, which found that voting in
Wisconsin apparently did not lead to a big spike in cases. We don’t know how many of the voters were
wearing masks, but probably at least some.
So this isn’t an indication of what will happen with restaurants. But it
is probably more exposure to other people than one would experience going to a
store, given that people were waiting in line to vote for hours.
So my prediction for Tennessee is that there will be an
increase in spread now that restaurants are allowed to open, but I don’t think
it will be the high rate of spread seen in New York at the very beginning, or even
what we had at the beginning of the outbreak here, because most public spaces
are conducive to mask-wearing, and it appears that most people are now wearing masks in
them. I just don’t know if it will be higher than R0 = 1, which would give
increasing numbers of new cases over time. Again, I’m hoping that the older and at-risk people stay home until we see the results of the not-very-scientific experiment.
If you are someone who is highly motivated not to catch the virus, you can protect
yourself by wearing a mask, by sanitizing your hands and things you bring into
your house, and by not touching your face until you get back home. If you want to go the extra mile, you can
change clothes as soon as you come home.
It will be an annoyance, but your risk of catching the virus will be dramatically reduced.
