The COVID-19 Vaccine: When, Where, and Who?

 

Most experts agree that the only thing which will put the current COVID-19 pandemic to rest is some kind of vaccine.  One firm—Pfizer/BioNtech—has progressed to what is called a Phase 3 trial, which involved about 43,000 people who took it with apparently no serious side effects.  There is still a long way to go even with the most advanced projects, because achieving "herd immunity"—enough immune people to discourage the virus from spreading—may require on the order of several billion doses.  And many of the prospective vaccines require two injections spaced weeks apart, which further complicates matters.

 

Engineers are familiar with tradeoffs that are usually imposed by economic restrictions.  When I was a young engineer just out of college, I was teamed with an older and more experienced engineer, and one day we were talking about various possible ways to tackle a certain problem in a new design we were working on.  I described three or four different ways to tackle it that I thought were pretty clever, but he seemed unimpressed.  Finally, I asked him why he wasn't more excited about these innovative ideas I was proposing.

 

"Heck, I can build one of anything!  The real challenge is making thousands of them work at a price we can afford."  The harsh realities of the marketplace had educated him to look not just for technically sweet ideas, but for ideas—new, old, or otherwise—that would do the best job for the least money.  That taught me that having clever ideas—or one dose of a highly effective vaccine—is only a small step toward solving a real-world engineering or technical problem.

 

Making a billion high-quality vaccine doses in a short time is a challenge that hasn't been discussed much so far.  But supposing that vast production problem is overcome, and reliable vaccine doses begin to enter the pipeline, who is going to get them first? 

 

An interesting study cited by a recent BBC article says that the first doses should go to different groups, depending on how effective the vaccine is.  No vaccine is 100% effective, and this is especially true of virus vaccines.  The annual flu-virus vaccine that millions of people get is rarely more than 60% or so effective, depending on the particular year and the mix of viruses that show up after the vaccine is developed. 

 

There are different ways to measure the effectiveness of vaccines.  One way is to measure how many people who are vaccinated and then exposed to the virus develop symptoms.  Another way is to measure how likely a vaccinated and exposed person is to spread the disease to others, whether or not they manifest symptoms.  The study's authors point out that if you developed a vaccine that was only 30% effective in preventing symptoms, it would fall below the U. S. Food and Drug Administration's 50% threshold and wouldn't even be approved.  But if it happened to be 70% effective at stopping people from spreading the virus, it would actually do more good than a different vaccine that prevented symptoms with 100% effectiveness but allowed the virus to spread.

 

That is why there is no single answer to the question, "Who should get the vaccine first?"  If it is most effective in preventing the virus from spreading, then the target population should be the ones who spread it the most.  Currently that appears to be older children and younger adults, say between 10 and 35.  Few people in that group die of the virus, but just because many of them have either mild symptoms or are asymptomatic, they spread it very easily. 

 

On the other hand, if the vaccine is good at preventing symptoms but not so good at stopping the spread, you probably want to target the population that is most vulnerable to the disease:  people in rest homes and over 65.  That will save the most lives in the short term, while giving us time to vaccinate the rest of the population to approach the goal of herd immunity.

 

Any way you slice it, we face a very long uphill battle in fighting this disease.  In some countries such as the U. S. and China, the expense of buying and distributing the vaccine is relatively trivial compared to other things the government is doing.  But in poorer countries, vaccinating the majority of the population with anything is a major challenge, and so we can expect the disease to hang around in pockets long after it has been controlled in more economically well-off places.  So the last thing to go may be travel restrictions concerning COVID-19, at least to some countries where it may not be controlled for several more years.

 

Within a given country, the distribution of the vaccine may be implemented mainly by the government, mainly by private enterprise, or more typically by a combination of the two.  As it is in the interests of every government to free its citizens from the threat of COVID-19, substantially free distribution would seem to be a no-brainer, although there are practical obstacles to that as well.  Certain minority populations have been disproportionally affected by COVID-19, and the U. S. National Academies of Science, Engineering, and Medicine has stated that there is a "moral imperative" to make sure that this imbalance is addressed in any proposed distribution scheme. 

 

And last but not least, there is the problem that not everybody is going to want to be vaccinated.  We are a long way from the 1950s, when Jonas Salk was universally praised as a god-like hero and millions of U. S. citizens gratefully took their children to receive polio vaccine injections without raising even a quibble concerning its safety.  Nowadays, the pronouncements of experts always inspire somebody on the Internet to say, "Sez who?" and the small but vocal opponents of any kind of vaccination have persuaded lots of people at least to hesitate before believing uncritically anything an expert says. 

 

Even with all these uncertainties, it does look like we we get a vaccine sometime, and eventually it will begin to slow down the spread of COVID-19.  As far as I'm concerned, it can't come too soon.

 

Sources:  The BBC published the article "COVID:  How close are we to a vaccine?" on Nov. 12, 2020 at https://www.bbc.com/news/health-51665497.  The New York Times published "Who should get a COVID-19 vaccine first?" at https://www.nytimes.com/2020/11/05/magazine/who-gets-covid-vaccine.html on Nov. 5, 2020. 

Are Immunity Passports In Our Future?

Here in the midst of the COVID-19 crisis, many of us are starting to wonder how it's going to end.  Just last Friday, Texas Governor Greg Abbott announced plans to lift certain restrictions related to the pandemic.  Regardless of what governments do, the big question people have is not so much what's happening to the economy in general, but this:  "When can I safely resume my normal way of life?" 

Some people never stopped working—notably many healthcare workers, first responders, and employees of essential businesses such as grocery stores.  But they have kept working while trying to protect themselves from the virus, and that doesn't always succeed.  For example, numerous meat-packing plants across the U. S. have shut down because of the spread of COVID-19 among their employees, despite the strict microbiological protocols that such packing plants have to observe. 

Wouldn't it be nice if there was a simple, cheap, fast blood test to tell if you have the SARS-CoV-2 virus that causes COVID-19? 

Lots of pharmaceutical companies around the world have rushed into production just such devices, referred to as point-of-care antibody tests.  Many of these are what the specialists call "lateral-flow assays."  You get a drop of blood from the patient and put it on an enclosed test strip.  As the serum flows along the strip it encounters some stuff that changes color if the blood sample has the specific antibodies that the virus in question provokes the body to make.  And a final strip turns color to verify that the stuff got that far, as a reliability check.  The whole thing takes only 15 minutes or so, and the tests can be mass-produced for as little as $3 each.

Already, governments and institutions around the world are using these antibody tests for finding out who has antibodies.  They are not intended to be used to diagnose COVID-19, however.  It takes your system a week or longer after infection to develop enough antibodies to show up on an antibody test.  So you can be walking around with COVID-19 and infecting other people, and still test negative on an antibody test.  The gold standard for having an active infection is still the laboratory-based polymerase-chain-reaction (PCR) test, done typically with a nose-swab sample that is sent to a high-tech lab, although there are point-of-care versions of PCR tests now available as well. 

But the test that is generating the most interest is the antibody test.  Presumably, a person with enough antibodies against COVID-19 is immune, although the truth of that assumption is actually still a research question that is currently being investigated.  As if that wasn't complicated enough, there are neutralizing antibodies, which confer long-lasting immunity, and binding antibodies, which just fight short-term infections.  Most of the point-of-care antibody tests detect only the binding antibodies, which indicate that you've been dealing with the virus recently.  Most people, but not all, go on to develop the neutralizing antibodies that confer immunity, but for how long, nobody knows yet.

Okay, so say I'm a manager desperate to get my factory back into production, and somebody comes along and offers me an antibody test.  I will be strongly tempted to require all of my workers and prospective employees to take the test, and only allow in the ones who test that they are immune.  Right now, that might not be a large percentage, but as time goes on and the hoped-for "herd immunity" develops, such a testing policy might be very tempting.  In effect, you'd have to have an immunity passport in order to go back to work.

Already, many health care institutions are planning to administer antibody tests, with the assumption that anyone who tests positive can't get COVID-19, or is at least much less likely to catch it, and so they might be the people you put on the front lines dealing with COVID-19 patients, reserving your non-immune staff to safer duties.

And let's get personal here.  What about teachers or others who deal with large numbers of people in close proximity?  When I was hired at Texas State University, I had to show that I passed a TB test.  That was to make sure I didn't have tuberculosis, which can be a chronic asymptomatic disease that can nevertheless be spread by otherwise apparently healthy people. 

With COVID-19, it's sort of the opposite problem.  Without a vaccine (and most experts think that's at least a year away), the only way you can safely start being in proximity with strangers on a routine basis is if most of the other people around you can't get COVID-19.  That's what herd immunity means, and we don't really know how far away from that we are, without widespread antibody testing of representative samples of the population, both apparently healthy and otherwise.

That's probably the best current use of antibody tests:  to monitor the average state of immunity in a geographic area with random sampling of both healthy and sick people.  That way, even if the tests aren't 100% accurate (and many of them fall short of that), you can factor the errors into statistics and still arrive at a pretty good aggregate number, and it doesn't matter if the odd result here or there is wrong.  In particular, it won't condemn to continued unemployment a person who has really had COVID-19 but the antibody test wrongly says he or she hasn't had it. 

A perverse situation might arise in which those of us, especially ones over 60, who have gone to extraordinary lengths to avoid catching the stuff, end up being sort of inverse Typhoid Marys.  Our employers might say, "Look here, I'll take back people who have had it and can't catch it, but you susceptible folks, you'd better stay away for a while longer until the herd immunity gets so high that it's unlikely you'll catch it regardless."  Maybe not every employer will think that way, but some of them will.

At this point, it looks like the antibody tests are simply not reliable enough to do such specifically targeted testing, especially if the results can mean continued unemployment or worse.  But look for problems to crop up along these lines, and where such problems show up, lawyers can't be far behind.

Sources:  I referred to an article on the website of the Journal of the American Medical Association by Jennifer Abbasi at https://jamanetwork.com/journals/jama/fullarticle/2764954.  The meat-packer shutdown is described at  https://abc7chicago.com/health/covid-19-outbreak-at-chicago-meat-packing-plant-sparks-calls-for-investigation/6114075/.