From roast dinners to seatbelts: Metaphors to address Covid-19 vaccine hesitancy – by Elena Semino

Professor Sarah Gilbert, who led the team that developed the Oxford Astrazeneca vaccine against Covid-19, has recently made this comment about different attitudes towards vaccines:

I don’t understand anti-vaxxers. Why should anyone be ideologically opposed to a safe and cost-effective public health measure that saves millions of lives and stops people from having to live with the long-term disabilities that can be caused by diseases such as polio and smallpox – and, it seems, Covid-19?

[…] Vaccine hesitancy, however, is a different matter. It is natural that people want to understand the risks and benefits of vaccines, and important that as scientists we engage with their concerns. (Vaxxers, by Sarah Gilbert and Catherine Green, 2021, p. 192)

One of the ways in which Gilbert and her co-author of the 2021 book Vaxxers, Dr Catherine Green, engage with those concerns is through metaphors. Many other scientists, science writers and health professionals have done the same.

Metaphors(1) make it possible to talk and think about abstract, complex and unfamiliar phenomena in terms of different phenomena that are more image-rich, clear-cut and accessible. In the case of Covid-19 vaccines, metaphors drawn from everyday experiences such as cooking roast dinners or wearing seatbelts in cars have been used to explain two specific aspects that can cause concern or confusion:

  • the unusual speed with which the vaccines have been developed, and
  • the fact that the vaccines are doing their job and are therefore worth taking up even if they don’t provide 100% protection.

Metaphors to reconcile speed and safety

The unprecedented speed with which vaccines for Covid-19 have been developed, tested, manufactured and rolled out is one of the scientific and organisational successes of the pandemic (as far as rich countries are concerned), but it is also a potential source of legitimate concerns about whether this has made the vaccines less safe.

A non-metaphorical response to this concern involves explaining how the development of Covid-19 vaccines was not affected by the lengthy delays that are normally caused by lack of resources, funding, trial volunteers and commercial investors. A metaphorical response usually involves a comparison with cooking.

Guardian columnist Gaby Insliff draws from our experience of restaurant meals:

A process that usually takes years when worked through sequentially – first the scientific breakthrough in the lab, then entering clinical trials, then winning approval from the independent safety regulator, then beginning production – is effectively happening all at once, as if a restaurant brought out your starter, mains, and pudding simultaneously. The cooking time for each is no shorter, but the meal isn’t half speeded up. (The Guardian, 16 November 2020)

In Vaxxers, Gilbert compares the development of vaccines to making a roast dinner. The process that applied to previous vaccines, she says,

is as if you are making a roast dinner and for every ingredient you have to make a separate trip to the shops to buy it, then cook it and demonstrate that it is going to be delicious, before moving on to the next. (Vaxxers, p. 157)

In contrast, with vaccines for Covid-19,

We were allowed to do a big shop and put all the ingredients we needed in the trolley all at once. (Vaxxers, pp. 157-8)

In the same book, Green uses a baking metaphor to explain the ‘rapid method’ for making a vaccine that Gilbert had conceived of prior to the pandemic, in the expectation that a deadly pathogen might at some point turn up:

Think about a baker who sells personalised cakes iced with a message like ‘Happy 50th birthday Joe’ or ‘Congratulations on your engagement Ali and Max’. She might wait until she gets an order, and only then start the process of mixing the ingredients, baking the cake, letting it cool, icing it all over, waiting for the icing to set, and then finally adding the customized message. If she gets the order the day before the cake is needed, that works well. But if she wants to be able to offer a quicker service, she could bake a stock of cakes and put on the base layer of icing every morning. She is taking a financial risk: if no orders come in, the pre-baked cakes will go stale and need to be thrown away. But it may be worth the risk. When a customer comes into the shop, all she has to do is pick up her piping bag and add the custom message while he waits. The cake is then ready to take straight to the party. Only in the case of a vaccine, the party is a pandemic. (Vaxxers, p. 66)

The cake, Green goes on to explain, is the starting material for a vaccine, which is generic. The personalised icing is the pathogen-specific string of DNA that is added to the starting material in order to produce a vaccine for that specific pathogen, such as SARS-CoV-2. As well as explaining the rapid method, this metaphor has another important function: it explains how the speeding up of the process poses a risk to the producers of the vaccine (who may have wasted time, effort and resources if the starting material is not needed) rather than the future recipients of the vaccine.

Metaphors to reconcile less than 100% effectiveness with the importance of vaccines

The second main area of vaccine-related concerns that metaphors are being used to address results from the fact that vaccines reduce, but do not eliminate, the possibility that one may test positive for Covid-19, develop symptoms, or even get seriously ill and die. This was in fact expected for vaccines against a coronavirus, but can nonetheless lead to the perception that vaccinations are pointless, or even fuel vaccine-related conspiracy theories.

This concern is being countered by means of metaphorical comparisons with other everyday experiences where we take preventative measures against unpleasant or dangerous things even if those measures are not totally protective. These include, for example, flame retardants and raincoats:

The second thing to know about the COVID-19 vaccines is that they’re flame retardants, not impenetrable firewalls, when it comes to the coronavirus. Some vaccinated people are still getting infected, and a small subset of these individuals is still getting sick—and this is completely expected. (The Atlantic, 13th July 2021)

Concerning breakthrough infections. Think of the vaccine as a very effective raincoat. If it’s drizzling, you’ll be protected. If the rain is coming down hard, you might still be fine. But if you are going in and out of rainstorms all the time, you could end up getting wet. (@sailorrooscout on Twitter, 13th July 2021)

While both metaphors aim to explain that vaccines are effective and worthwhile even if they do not provide total protection, the raincoat metaphor is additionally used to connect the risk of post-vaccine infection (getting wet) to the amount of exposure to the virus (how much rain one is exposed to).

Metaphorical comparisons between vaccines and seatbelts have also been used to explain not just the importance of less-than-perfect preventative measures, but also the need for caution in spite of those measures (driving carefully while wearing seatbelts) and even vaccine side effects (seatbelt injuries):

Do seatbelts prevent you from danger?

No, wearing a seatbelt does not prevent an accident. In the same way, getting vaccinated does not prevent you from getting infected.

If you get into a car accident, does wearing a seatbelt reduce severity?

Yes, if you get in an accident, your seatbelt will decrease the chances of severe injury. Similarly, the COVID-19 vaccine protects you from experiencing more severe symptoms of the virus.

Does wearing a seatbelt mean you should drive recklessly?

No, when you are wearing a seatbelt, you still follow safety precautions to decrease the chances of getting in an accident. Getting vaccinated does not mean that you should stop wearing a mask and social distancing.

Can you have seatbelt marks when you get in an accident?

Yes, seatbelt injuries are possible. The COVID-19 vaccine may have initial minimal side effects while your body uses the vaccine to build immunity to the virus. (

Will these metaphors work?

We know from previous research that the most effective metaphors draw from a familiar and well delineated area of experience, and involve clear correspondences between that area of experience and the topic. The metaphors I have quoted inevitably reflect what is familiar to their producers (not everyone makes roast dinners or wears raincoats), but they do generally draw from experiences that will resonate for the main audiences for which they are intended, and still be accessible beyond that (most people know about cooking and about sheltering oneself from the elements). In addition, the ways in which the components of the metaphorical scenarios match the topics are fairly intuitive, and they are often spelt out explicitly (e.g. the cake and the vaccine starting material, or mask wearing and driving cautiously while wearing seatbelts).

There is a third condition for the effectiveness of metaphors, however. Metaphors tend to be more effective when the recipients do not already have strongly held views about the topic captured by the metaphor. In the case of vaccines, even the clearest and most accessible amongst the examples I have discussed are unlikely to persuade the people that Sarah Gilbert says in Vaxxers that she does not understand: those who are ideologically opposed to vaccinations, for various different reasons. However, these metaphors may well play an important role in reassuring and persuading the people that Gilbert says she does understand: those who are genuinely and legitimately concerned and conflicted about vaccines, and who deserve clear and honest answers. That is where metaphor can be a useful tool for reducing vaccine hesitancy and increasing the take-up of vaccinations.


(1) I use the term ‘metaphor’ to capture talking, and, potentially, thinking about one thing in terms of another, where the two things are different, but some similarities can be perceived between them. In linguistic terms, this includes metaphorically used words, similes and other forms of non-literal comparison.