Reason Interviews

Alex Tabarrok on 'First Doses First'

"When you push out the first doses faster, you get to herd immunity faster."


The COVID-19 vaccines made by Moderna and Pfizer/BioNTech were developed and brought to market at a blistering pace, but their distribution has been hobbled by poor organization and rigid eligibility rules. The planned rollouts didn't give local officials and health care workers enough flexibility to adjust to the realities on the ground—or to make tradeoffs between treating as many people as possible and strictly adhering to the guidelines.

Alex Tabarrok, an economist at George Mason University who blogs at Marginal Revolution, has been promoting an idea called "First Doses First," which the United Kingdom recently adopted. This approach would allocate all available vaccines to be used as first doses, while pushing off second doses for weeks (or even months) until production can catch up. While U.S. regulators have so far resisted the strategy, they recently eased up on strict rules about the timing between doses.

Reason's Isaac Reese spoke to Tabarrok in January about the vaccine situation.

Q: You argued that the world's governments should collectively spend about $100 billion on vaccines. Where does that number come from?

A: The economics of this is actually incredibly simple: The world economy is losing $500 billion to $1 trillion a month. A month. So it's billions of dollars, invested in vaccines, to save trillions of dollars by accelerating the recovery.

Q: You consulted for the Trump administration, the World Bank, and other foreign governments about how to spur vaccine development. Can you talk about the advice you offered?

A: We initially approached it by thinking about an advanced market commitment, which is what [economist and Nobel laureate Michael] Kremer had used to increase the incentive to produce a pneumococcus vaccine. You set a high price, and then you just wait for firms to jump into the market to try and achieve, like a prize.

We quickly discovered that that might not be optimal in the current situation. The economic costs [of COVID-19] were so high that you wanted a lot of shots on goal, and you even wanted to take some shots with a low probability of success. But if you have a firm with an extremely low probability of success, to pull them into the market requires a very high prize at the end. If you can't tell which firm is which, that means you need a really big prize for all of the firms, whether they have a high probability of success or a low probability of success.

Q: You've been pushing an idea called "First Doses First." What does that mean?

A: "First Doses First" is pretty simple. The way the clinical trials were designed was that the first dose of the vaccine is given, and then 21 or 28 days later, depending upon whether it's the Pfizer or the Moderna vaccine, you get the second dose.

It takes the body's immune system some time to respond to the vaccine and to build up its strength. However, after the first 10 days, but before the second dose was given, what we saw is that the vaccine looks extremely effective. It looks to be 80–90 percent effective [after the first dose]. It's about 95 percent effective after the second dose.

That means you can give twice as many first doses if, instead of giving a second dose, you give a first dose to somebody else. You can have two people who are protected at an 80 percent efficacy rate, as opposed to one person who's protected at a 95 percent efficacy rate.

When you push out the first doses faster, you get to herd immunity faster. So the more you spread out the first doses, the slower the transmission rate of the virus is, because now fewer people are getting the disease, and it looks then that fewer people will be transmitting the disease.

This interview has been condensed and edited for style and clarity. For a video version, visit

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  2. With a government headed by a senile old man dependent on the advice of a self-confessed liar, reaching herd immunity is irrelevant.
    All government intrusions into individual freedoms will continue and probably increase.

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  3. In the 90s, my military unit announced that we would be getting a new vaccine while we were in Turkey. A guy in my unit told them that he wasn’t taking the vaccine. Over the next few days, they threatened him repeatedly, “How dare he”? He told them to go chase themselves. Our entire chain of command flew in. Weird, huh? They flew to Turkey, just to threaten this lowly Sergeant. Again, he told them to chase themselves. He was a bright guy and knew all the regulations. He ripped their arguments to shreds easily and threatened to call the Inspector General.
    As it turns out, the vaccine was experimental, they were going to test it on us. They do it to basic training classes because they won’t talk back. The guy who said “no” was a former Drill Sergeant and he saw this happen.
    A day later. It all ended. The scumbags in our chain of command left, and our chain of command never mentioned the vaccine again. None of us took the vaccine. I’d never seen high ranking scumbags get humbled like that. Up until that time, I trusted vaccines and never thought twice about taking them. After that, I questioned everything.
    Think about that. A low ranking Segeant told a pack of gut eating Colonels and brown nosing Sergeant Majors “No” concerning a vaccine and they skittered off. They took no legal action or UCMJ because they couldn’t.
    After seeing that, I am not nearly as quick to take medications that the government is pushing. Honestly, I’d rather take my chances with Covid than trust these government rats.

    1. Honestly, I’d rather take my chances with Covid than trust these government rats.


      They can’t make us take it. However it’s already a condition to travel, will be a condition to go to school, and who knows what else they’ll dream up. We won’t be compelled to take the vaccine, but if we don’t we won’t be allowed to participate in society.

  4. as I’ve pointed out elsewhere, the concentration of mortality risk in the CDC “at-risk group” is so high FDF makes no sense, except in the context of “FDF for the at-risk, second shot for at-risk, then FDF for everyone else”

    the math is absurdly straightforward, when you remove the at-risks from the younger populations their risk drops so low we can barely measure it

    conservatively, the median at-risk is around 10,000x more likely to die than the median not-at-risk

    thus the second shot for the median at-risk has far, far more potential to reduce mortality than the first shot for the not-at-risk, even if the second shot provides less than 1% more protection, which is unlikely

    1. Right. “First dose first” would make sense if the supply were that low compared to the at-risk pool. But as it is right now, you’ll run out of at-risk population well before you run out of first doses. So hewing to FDF is going to be trivial, making no difference as long as the other priorities stay the same.

      1. vaccine supplies are still limited, for now

        but fortunately we actually have, in fact, just about run out of at-risks for a second shot

        at least in the US the at-risks have largely already been scheduled for their second shot

        the decision between “FDF for all” and “at-risk second shots first” had to be made many months ago

        “FDF for all” was clearly not the right decision

  5. How to distribute COVID vaccines?

    1. Science and math (mostly). Around 90% of COVID deaths have been in those 60 or older, and mostly those with existing serious health problems. For those under 60 (and especially under 40) the risk of dying from COVID is less than the risk of dying in a vehicle crash. So, first vaccinate seniors and maybe health professionals directly involved in caring for seniors.

    2. Politics, marketing, and propaganda. People of all ages have at best confused understanding of COVID risks, and most have exaggerated concerns. Use vaccine distribution as part of a new propaganda campaign. (But that could either try to ease fears and encourage people to live more freely, or continue to promote “concern” and emotional dependence on authority.)

    1. And of course exclude those who you can be sure already have natural immunity. But don’t waste time testing for natural immunity in iffy cases, just vaccinate them. There are many cases where it can be quickly established that they’re immune, either by history of confirmed diagnosis or by circulating antibody titer. There are many more who don’t have those signs but have T cell memory of SARS-CoV2, but it will take too long to determine who does when you could just vaccinate and be done with it.

  6. “When you push out the first doses faster, you get to herd immunity faster.

    *Ron Bailey furiously searches for statistics to refute this outrageous claim*

    1. yeah purely speculative

      at-risk are going to shed a lot more virus when infected and have far more contact, on average, with other at-risks

      dry tinder burns a lot easier than concrete, spray the wood first

      seems likely that immunizing Joe Fratboy while Grandma Diabetic waits for her second shot will quickly become “Cuomocide: the Sequel”

      1. Cuomocide would be the killing of Cuomo, which I would never publicly support. In public. Where others would hear.

  7. Maybe the immunologists and virologists who developed the vaccines know something about how they work and recommend the schedule for second dosing based on this knowledge.

    Sounds crazy, I know.

  8. This discussion never ever seems to cover the most important point, which is that the first dose has not been proven to last. The second dose is essential for enduring immunity because it is the one that says to the immune system “Yes I really mean it, get busy and make the enduring immunity”, A single dose has a short term effect that will not last without the second dose, so giving two people a single dose could result in two people with fading immunity who will become vulnerable again. I do not know any data on this point with respect to the Covid vaccine but without this data, FDF might end up a disaster for the country. Do it right the first time!

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