You're vaccinated. What is it safe to do now?

April 25, 2021 By Alan Salzberg

Vaccinated people can and should live completely without restrictions regarding masks, gathering, and social distancing.  They pose virtually no risk to themselves or others, and their re-entry would help us get to herd immunity faster.

Let's look at the numbers.

First, we have known for sometime that the vaccines are very effective.  I'm going to focus on Pfizer and Moderna, because they comprise the vast majority of US vaccinations.  After the initial clinical trials only looked at symptomatic infections, there was a small concern that the vaccinated might be able to still get COVID at similar rates and pass it on.  This concern has been proven unfounded by multiple studies, which have concluded vaccinated people are very very unlikely to contract either symptomatic or asymptomatic COVID.  Studies by the CDC (news release about it here: ) and the Mayo clinic ( are but a couple of examples of many studies.  These studies consistently show about 90% effectiveness, meaning people studied with the vaccine had about 1/10th the rate of infection as those without.

Let's calculate what this means in terms of chances of getting infected on a daily basis.  Right now, there are 75 million fully vaccinated people in an exposed population of a little over 300 million and there are about 50,000 confirmed infections per day.  If we assume the 1/10th rate found in studies, we can calculate the daily vaccinated infection rate r algebraically: 50,000 = 10r*225MM + r*75MM .  the 10r denotes the infection rate of those not vaccinated, which is applied to the 225MM, versus the vaccinated rate r, which is applied to the 75MM.  Doing the algebra (surely you remember how), we get an r of about 1 in 50,000.  At this rate, a vaccinated person has less than a 1 in 100 chances of contracting COVID over a year, far lower than the chances of contracting the flu (even when vaccinated for the flu) in a typical year (and also far lower than the chances of dying from the flu in a typical year).

But the rate might actually be even lower.  Recently the CDC has said that only 5,800 fully vaccinated people have contracted COVID (see over all time.  In order to figure out the chances of getting COVID for one vaccinated person on one day, we need to know the person-days (number of people fully vaccinated times number of days they have been fully vaccinated on average) of exposure.  To know that, we need to know how long people have been vaccinated.  

It is difficult to figure out the average time the fully vaccinated have been vaccinated, but we can conservatively compute it, knowing the real number is higher.  We know that now about 1.5MM more are fully vaccinated each day.  What does this mean?  About 20 days ago, 30 million fewer were fully vaccinated (meaning 45MM have been vaccinated for at least 20 days).  Continuing backward, and assuming 1.5 million more were vaccinated each day, we can compute the total number of person days of exposure for the current (as of a few days ago) 75 million people who were fully vaccinated.  This total (which conservatively says no one was yet fully vaccinated on March 1) is about 1.9 *billion* person-days of exposure.  This means that the chances of a fully vaccinated person being infected in the US has been about 5,800 divided by 1.9 billion.  This is less than 1 in 300,000.

So now we have two numbers: 1 in 50,000 per day by applying the 90% from real-world medical studies and 1 in 300,000 per day from disease tracking by the CDC.  I suspect the difference is that the higher rate found in the studies is due to higher exposure (some portion of the studies were concerning medical workers and other people likely to have higher than average exposure).  It is possible that higher exposure could mean a smaller difference in relative risk.

In any case, whether 1 in 50,000 or 1 in 300,000, or somewhere in-between, the risks are vanishingly small.  And if we look at the risk of getting a bad enough case that you are hospitalized when vaccinated, it is around 1 in 4 million per day.  Of dying?  About 1 in 30 million (these figures are based on the CDC figures of 296 hospitalized and 74 deaths among fully vaccinated).  We are in "chances of getting hit by lightning" territory right now.

If you're vaccinated, it's your social *obligation* to get out and party!

So it's clear you are at little risk of getting COVID when vaccinated--low enough that you need not worry about either getting it or giving it to someone else.  

I'm going to go further though.  If you care about ending COVID and you're vaxed, you have an *obligation* to get out there and party.  In most of the country, most everything is now open, and vaccinated people at this moment appear to be more conservative in terms of interacting in public than unvaccinated.  This means bars and restaurants are mostly filled with unvaccinated people, giving many opportunities for exposure.  Vaccinated people provide an infection barrier to the unvaccinated, so by crowding the bars, the vaccinated will ensure the unvaccinated who are also there have a lower chance of contracting COVID.  In other words, by getting out and partying as a vaccinated person, you might be saving an un-vaccinated person from COVID, and therefore, saving lives!