COVID-19 Vaccines and Variants - a few thoughts
Vaccines and variants are in the COVID news these days, so I figured I would write and tell you a few things. I don’t know if we will ever completely go back to pre-pandemic “normal”, but I’m certainly optimistic that things will get better, and I’ll tell you two reasons for that at the end of this article.
Of course, like all COVID news, everything has to be read with a good helping of “we don’t know for sure just yet”. Sorry, that’s the nature of the beast. If you are a politician or a health policy official making good faith efforts to save lives while avoiding unnecessary restrictions, you have to work with "we don't know yet". Some things just take time, no matter how much money or authority you throw at the problem.
What we want is herd immunity. That means that enough of the population has enough immunity against an infection so that new outbreaks are quickly contained. And THAT means that it doesn’t spread widely, even among people who don’t have immunity because they weren’t vaccinated or infected in the past.
I found a very useful online simulator that can help you understand some of the issues involved with herd immunity, as we ramp up our vaccination efforts and as all of us make our best efforts to bring this monster under control. The simulator shows how quickly a virus spreads in a population with different baseline assumptions. These assumptions are things that we are learning about COVID-19 every day. They help us make better and better guesses about the future of the pandemic, and to make the best informed policy decisions right now.
For example, we often assume that past infection means lifelong immunity. While that may be the case in some diseases (like measles), no one in the world has any long term experience with COVID-19. We also don’t know how much past infection (or vaccination) protects against each new variant as they develop. On the other hand, we do know that antibody levels drop over time. We also have to understand exactly what each new COVID-19 strain implies - some may be more contagious, some may have a degree of resistance to current vaccines, and some may be more dangerous if you get infected.
As of this writing, there are three main variants, named after the countries of origin: United Kingdom (B.1.1.7), South Africa (B.1.351) and Brazil (P.1). It seems that these may spread more easily than the original strain. Also, while it does seem that the antibodies generated by the current vaccines recognize these variants, there are early concerns that they may be more lethal and less susceptible to vaccination control. Fortunately, the mRNA vaccine production technique is well suited to quick modifications, if these strains become more prevalent.
Fighting this pandemic means tracking a moving target, and continually monitoring the real world data. We do that by sequencing specimens recovered from patients, to go beyond the standard PCR positive or negative results to detect new variant strains. Unfortunately, this hasn't been done as much in the US as in other countries, but there are efforts to ramp that up quickly, and Congress is moving to fund those efforts.
Remember, anything that you can do to stop a new case of COVID-19 stops the process that causes these new strains to evolve. They develop when the virus reproduces in our bodies, mutates, and one of these mutations becomes more successful in reproducing further. And in addition to stopping the DEVELOPMENT of new strains, it is also crucial to prevent the SPREAD of these strains. To do both of these, do good hand hygiene, watch your social distancing, and MASK UP!
So let’s finish up with some potential good news - too early to celebrate, but here are two things to watch.
As you may know, Israel is far ahead of every other country in terms of the percentage of people vaccinated. So that means that some of the first real world data will probably come from there. This past week, an early version of an Israeli study suggested that the vaccine cuts ASYMPTOMATIC TRANSMISSION by almost 90%. Now remember, this work has not been reviewed, and there are some serious concerns about reading too much into this yet. I normally wouldn’t talk too much about unpublished data like this. But since it has been making so much news, I thought I should tell you why - if this turns out to be true - it would be so great.
The Pfizer and Moderna mRNA vaccines were developed incredibly quickly, and they still went through all of the necessary testing to prove safety and efficacy. But what question was asked to find out if they are effective? You could either ask “do they keep you from getting hospitalized and/or dying from COVID-19?”, or “do they stop you from spreading the virus to other people?” Researchers primarily focused on the first question, for two main reasons.
First of all, the main goal here is to save lives, and that means proving that the vaccine does that and get it into people's arms as soon as possible. Second, it's far easier to track hospitalizations and deaths than it is to track infections. To see if a vaccine changes the rate of all (even asymptomatic) infections, you would need to swab the thousands of people in your study group again and again, which is incredibly expensive and very invasive. Insisting on answering the second question before launch would have costs time and lives.
This also means that even if someone gets a vaccine and then gets infected, THAT DOESN'T MEAN that vaccines "don't work". They have essentially eliminated serious illness and death in fully vaccinated populations. Someone getting a vaccine and then having a mild or asymptomatic COVID infection makes for good clickbait, but it's meaningless from a clinical or health policy point of view. We should all appreciate the incredible achievement that these vaccines represent.
So if this Israeli study holds up, that means that not only will a vaccine prevent you from dying from COVID (important!), but it will prevent you from SPREADING the virus, and will prevent the development of new resistant strains. Fingers crossed. If you want to read an excellent article about how vaccines will eventually stop the spread (no matter what happens with the Israeli data), check out virologist Angela Rasmussen's piece in the Times today.
The second bit of potential good news to watch for is scheduled for February 26th. That’s when the FDA will meet to consider the Emergency Use application for the Johnson and Johnson single dose adenovirus vaccine, which could be authorized by early March. Clearly, having three companies making vaccines instead of two will move us even faster towards getting this pandemic under control.
Once more, it is STILL important to mask up, wash your hands, and watch your exposure (being indoors with people outside of your household, etc…). The more infections there are, the more chances the virus has to evolve and develop new variants that are resistant to the vaccines and treatments that we have now.
Lets do this!