I recently received my second of two COVID-19 vaccinations, which happened to be from Pfizer/BioNTech. Although it’s a big relief, and I’m much better protected now, it doesn’t mean it will change much that I do for a while. Let me explain why.
Vaccines don’t act right away. The way they work is to prepare your immune system to recognize something that is bad for you, so if it arrives your body is ready to attack it. But it takes time to do this. Imagine you’re running a race and someone is trying to chase you down before you can cross the finish line to safety. The faster they are, the more head start you need. What makes a bacteria or virus faster, besides the basic nature of it, is how much of a head start it has, which is basically how much of it you’re exposed to. It’s an over simplification, but supposed the virus doubles every 6 hours and you initially breath in 10,000 virus particles. After 5 days you’d have about 10 billion of them. After one more day you’d have close to 168 billion, a massive increase. So you have to have enough of a head start that the virus can’t grow to the point of overwhelming you. Every day after your initial vaccination is that much more of a head start.
Another way to look at it is to imagine you body is a village and a company of hostile enemy soldiers shows up. They would quickly overrun and capture the place. But suppose these soldiers were not not yet nearby but you knew they might attack. You’d have time to enlist people to provide more security, train them what the enemy looks like, and set up additional lines of defense. Then if they were to attack it’s likely you’d successfully fend off the attack, though you might be a little worse for wear as a result. But if they attacked with a larger force, such as a battalion, they could still overwhelm you.
So you can think of getting a vaccine as giving you a greater head start, or having more bodyguards. That should protect you from most situations, but you still wouldn’t want to run the risk of getting a massive exposure, or perhaps being someone who didn’t develop a good response to the vaccine. So wearing a mask, maintaining distance, etc. all minimize the risk. We don’t know yet how much exposure it would take to actually get someone sick if they have been vaccinated with sufficient time to be fully effective, so my concern now is just theoretical, but there are other reasons to remain cautious, particularly until the number of cases in one’s community falls significantly.
For one thing, the vaccine was 95% effective in the studies. That’s impressive, but it still means 1 out of 20 were infected sufficiently to have symptoms. For another, we don’t know if vaccinated people can subsequently get infected and not have symptoms, but be capable of spreading it to others. Finally, people who have not yet been vaccinated may feel anxious, or resentful, seeing people who are not wearing masks.
Some of my patients have told me they are concerned about the vaccine, and some of have even decided they just won’t get it. Let me address some of the concerns. One worry is the vaccine was rushed and they don’t know if they can trust it. Although it was rushed, it was mainly from everyone working longer hours than usual, companies prioritizing the research and production, and governments willing to promise to buy vaccine before before approved, with the risk that they could have spent billions on something that would never be used. The FDA did approve it before having longer term studies than usual, but given the risk of not being vaccinated, it was the right thing to do.
Although sore arms and flu like symptoms are relatively common, particularly after the second dose, serious reactions are very rare. You shouldn’t look at the risk without considering the context. Without a vaccine you have a high chance of getting infected. Those infected have a relatively high risk of serious complications, including death, particularly if older, or have various medical conditions. Those at the lowest risk of getting COVID-19 or getting significantly sick, will be the last to get it the vaccine, which means they will have the benefit of there being more experience with it. Even if you are not worried for your yourself, getting vaccinated is good for the community. We need to get a high proportion of the country vaccinated to reach herd immunity so the virus can no longer take off. Unfortunately there have been a lot of misinformation spread about the coronavirus pandemic, and politicization about it, but that doesn’t mean that these are not excellent vaccines.
I’ll have to see what happens, but between having been vaccinated, and the pandemic probably being much better controlled, I hope that I’ll finally be able to take a real vacation by this fall.