Up to the present moment, the problems with vaccine have been largely about supply. More people want to be vaccinated (in total) than doses which are available right now. But — slowly — we are starting to see this ease up. And in more and more places, we’re seeing the first hints of softer demand, places opening up vaccines to all age group because demand is waning among older people. My emails, where until recently vaccine questions clustered around when one would be eligible, have subtly shifted to “What do I do, having just realized my parents refuse to be vaccinated?!”

People are finding themselves “parenting up” (HT Kelly Fradin), simultaneously trying to make sure the 18 month old doesn’t eat the five year old’s marbles while explaining over the phone that, no, a mold allergy does not rule out vaccination.

With this looming, I thought it would be useful to talk through issues of vaccine resistance, both from a policy standpoint and in our personal lives. This piece is long, so here’s a TL;DR outline:


  • We don’t know an exact “herd immunity” number, we may never, and our focus should be on vaccinating as many people as possible as quickly as possible without worrying about some threshold number.
  • Making vaccines accessible & easy & providing some incentives (donuts!) should be the next phase of vaccine push. Let’s wait to worry about the hard-core resistance until we make some progress on groups who are willing but not breaking down the door.
  • If it is your family who is hesitant, you can try to provide them information. But in the end, you may need to make a thoughtful decision about the limits you want to set, and stick to them. You can combine this with the healthy approach of screaming obscenities into your pillow.

Herd Immunity

“Herd immunity” refers to the situation where enough people are immune — either through infection or vaccination — that disease protection extends to the non-immunized. The share of the population who needs to be immune in order to deliver this varies by disease; if a disease is very infectious, a larger share of the population needs immunity in order to protect the unvaccinated. For measles, for example, most estimates suggest we need over 90% vaccination for herd immunity. This number is lower for the flu.

It is unclear what the COVID-19 herd immunity level is. In writing this, I asked two experts I really trust and one told me 50% and the other 80 to 85%. This is a big range! Most estimates I have seen are around 60% to 70% but, again, it isn’t clear what this is based on.

Perhaps more importantly, moving from a herd immunity number to a “number need to be vaccinated” is difficult.

This translation depends, first, on the vaccine efficacy against illness. If a vaccine is 95% effective against any disease then you’d need 63% vaccinated to get to 60% immune. If the vaccine is only 80% effective, then you’d need 75% vaccinated.

It also depends on the share of people who have already had COVID-19, since they are also protected even if they aren’t vaccinated. Beyond this, it depends on the correlation between vaccination status and past COVID-19 illness. If the vaccine-refusers are the same people who already had COVID then that’s (paradoxically, perhaps) better for public health because they have some immunity (they should still be vaccinated).

Other factors — spatial distribution, for example, and levels of interaction —also matter.

But even without knowing all these factors, it seems likely herd immunity will be a challenge in the short run. Twenty percent of the population (kids under 16) are not vaccine eligible yet and there is clearly some pretty staunch vaccine resistance in the US (not to mention low vaccination rates worldwide).

In my view, however, the focus on some (unknown!) herd immunity number should be put aside in favor of a focus on vaccinating as fast as possible. This particular number is neither a magic bullet nor necessary to make enormous progress.

Israel has 50% fully vaccinated as of last week and clearly, there are huge benefits to this vaccination, even if we do not think it’s at herd immunity threshold yet.

On the flip side, 80% immune is better than 60%, even if herd immunity kicks in at a lower level. Herd immunity also doesn’t mean zero COVID and strategies like testing are going to continue to be important for months and years to come.

The exact herd immunity number may be of academic interest, but our goal should simply be: more vaccines.

How Can we Encourage Vaccination?

Okay, so: how to increase vaccination rates?

More supply is the first answer. But encouraging demand is going to be necessary. The most stark fact for me is that 25% of the US House of Representatives has not chosen to be vaccinated despite months of eligibility. This is bad.

I’ve found it helpful in thinking about this problem to consider, basically, three broad groups: the vaccine-eager, vaccine-neutral and vaccine-hesitant. This is a simplification! But it might help us think about solutions.

The first group, the vaccine-eager, really want vaccines. Some of this group has already been vaccinated; the already vaccinated group has been disproportionally white and wealthy, almost certainly due to access issues. If you need to be up at 2:30 am refreshing seven websites to get an appointment, that’s going to favor certain groups. This aspect of the roll-out has been unfair. As we look to expansions in supply, we should be mindful of how we use them. Hopefully, such expansions will mean that within a few weeks anyone who really wants a vaccine can get one.

The second group I’m going to call the vaccine-neutral. People who aren’t actively opposed to the vaccine, but aren’t seeking it out, either. I’ve been doing some volunteering at a vaccine clinic, helping people sign up for second doses. When I ask people if they’re happy to have a first dose, some definitely are, but for many others it’s just…fine. They’re not anxious or unhappy, it just doesn’t seem that important.

There is a policy temptation (at least among some) to try to convince this group that vaccines are important. This is a nice goal, but it’s probably very hard to do, in part because this group just isn’t thinking about this that much.

I would suggest that, instead, we simply try to make it easy and provide incentives. What would this mean?

  • Ease of Access: Better sign-up procedure. More pop-up sites. More accessible locations. More use of the one-shot Johnson & Johnson vaccine in places where it may be hard to get people to return for a second dose.

    Example: There has been a lot of bemoaning of spring break crowds in Miami Beach this week. I obviously agree this behavior is not COVID-appropriate, but what if we got some mobile vans with J&J shots down to the party venues?

    We are going to need to start bringing the vaccine to the people, rather than asking them to find it. Improving access will also start on the path to improving vaccine equity, since we can hopefully target pop-up sites to underserved areas and communities of color.

  • Incentives: Give people stuff for being vaccinated. Example: Krispy Kreme says you can get a free donut every day if you’ve been vaccinated. Some of the fun police oppose this on the grounds that donuts are bad for you, but I think it is great. Publix has offered its workers monetary incentives to get vaccinated. At a minimum, employers should give their employees time off for vaccination.

I’m sure I’m missing other creative ideas. Bottom line: make it easy, make it fun(ish). This is something we can start thinking about now, and should be our next top priority. It should be possible to get this group vaccinated, if we do it right.

Then we get to group 3: the vaccine-hesitant. (I do not like the term anti-vaxxer; it’s politicized and unnecessarily pejorative). There was a lot of talk initially about vaccine hesitancy in the Black community, which has historic reasons to distrust vaccines and health care in general. As vaccines have rolled out, though, this seems to have improved (see this article as an example) and there is a hope that addressing issues of access will improve this further. In the most recent data, vaccine resistance lies much more along party lines than anything else.

What can be done? For people who are nervous rather than actively opposed, progress can probably be made by simply waiting and exposing the vast number of safe vaccines which have been administered. Role models may help. This paper shows that Black men are more likely to sign up for preventative care services if matched with a Black doctor; if this extends to COVID vaccination, vaccine promotion efforts like this one are crucial.

The more actively opposed are much harder. We know from childhood vaccine resistance that giving people in these groups information about vaccine safety tends to actually backfire.

In the end, the last mile of vaccines may have to happen with more active encouragement. After a large measles outbreak in 2015, California ultimately achieved high vaccination rates in schools by, basically, mandating them. I’m not suggesting we do this now (in fact, it would be impossible given that the vaccines are approved only under Emergency Use Authorization). But as we look to the long term, it is something we need to consider.

What about my family members?

It’s all well and good to write about how we can impact vaccine rates with policy, but what if it is your parents (or sister or uncle or etc, etc.) who doesn’t want to be vaccinated?

(Related questions have come up with caregivers; this is an overlapping but slightly different situation. Similarly if the resistant party is your partner and not some more extended family, it’s different. I’m going to focus on the extended family situation here, but there are always alter posts…)

Obviously if the issue is access, then that’s something you can help fix. But the questions I’m getting these days are not about inability of family members to access vaccines but about their active opposition.

I do not have a magic bullet. This is a hard problem. It is frustrating and annoying. No one can drive us crazier than our own family. Take a deep breath.

I have two thoughts on framing here, which may help.

First: You do not need them to agree with you, you just need them to get the shot. This lesson is in part why I started with the policy discussion. When we think about the the “vaccine neutral” group above, we should fight our instincts to spend time convincing them vaccines are great. Who cares? If people get the shot, then they have it.

It may drive you out of your mind that one of your parents thinks the Pfizer mRNA delivery technology is some kind of liberal voodoo, but if they’ll get the Johnson and Johnson vaccine because they trust the company then that is fine. Paradoxically, arguing about the merits can make people dig into their position and make things worse.

Second: you can control the rules for your family, and that’s about it. In the end, if relatives will not be vaccinated, all you can do is set your own limits. It’s not dissimilar to how people advise setting them with kids: take time to decide what your rules are, what you feel safe and comfortable doing, and then be consistent.

Here are some possible rules:

  • No grandchildren visits at all until grandparents are vaccinated, period.
  • No indoor visits until grandparents vaccinated
  • No indoor visits until grandchildren vaccinated
  • Visits only with 10 day quarantine & testing in advance [i.e. as if vaccines do not exist]
  • Visits only with 7 day quarantine, testing, and only if case rates are below some threshold
  • etc, etc

There are infinite possibilities here, and what you decide is going to depend some on your risk tolerance, some on the situation in your location and some on your relationship with said relatives. You might hold a harder line with a more distant relative, where seeing them isn’t as important. Your rules may be different if you (the adults in the household) are vaccinated. It may also matter if the people in question have had COVID-19 illness; recovered people should still have the vaccine, but previous infection confers some protection.

As with most of my advice about decision-making, I’d suggest you take time with this, make a decision that works for you and then stick to it and move on.

The pandemic has provided many moments when control is wrested from us and this may be another. It’s frustrating to feel like there is a solution available and someone isn’t taking it for reasons which seem wrong or crazy to you. But like with everything else, there is value to recognizing what you can control and working on that.