Punctuation might help

A recent advert by the UK government and the NHS (National Health Service) is a classic case of garden path sentences. When I first read it, I thought it was saying Side effects won’t stop you catching COVID-19. But then I realised there was an extra word (might) at the end.

I went back to the beginning and discovered that the message was in fact two separate sentences:

  • Side effects won’t stop you.
  • Catching COVID-19 might.

Why is the advert unclear?

The advert contains no punctuation. To show that this message consists of two sentences, it relies solely on a difference in font colours (white for the 1st, orange for the 2nd). A full stop (period) at the end of the first sentence would have shown the split between the sentences much more clearly.

Linguists call this type of string of words a ‘garden path’. The words lead the reader initially in the wrong direction (they lead the reader ‘down the garden path’). The reader then has to back track when she realises she has mis-interpreted the sentence’s structure.

Another example of a garden path

A well known example of a garden path sentence is The horse raced past the barn fell. After reading the first 6 words, it is natural to construe the horse as the subject of an intransitive sentence: The horse raced past the barn.

However, on reaching the 7th word (fell), the reader realises that this additional word can’t fit into that structure. After brief confusion, the reader tracks back to the beginning of the sentence. Ultimately, the reader realises that the horse is in fact the subject of the verb fell and is the antecedent of the relative clause raced past the barn. Said differently, the sentence actually means The horse that was raced past the barn fell. (The horse was raced past the barn and the horse fell.)

And another thing

Lack of punctuation isn’t the only problem with this advert. It uses all capitals (upper case letters). I was taught that using all capitals is unhelpful to readers because capital letters have the same height. Thus, they take longer to recognise and to distinguish from each other.

And in this particular case, using putting all letters in capitals deprives readers of another clue that the word Catching is the first word in a new sentence.


Maybe the drafters of this advert deliberately made it difficult to read, so that readers would spend longer reading it and, as a result, internalise the message more thoroughly. That could sometimes be a valid strategy.

In this particular case, though, I doubt whether that was the strategy. I expect the drafters and designers wanted to make the message both stand out and be easy to read. If that was the intention, the drafters and designers failed. They led readers down the garden path for no reason.


  1. Definitely agree, the NHS’s message is poorly worded.
    But I’m not sure the first sentence is saying “Side effects won’t stop you catching COVID-19”. The side effects in question are those from getting a Covid shot. I think the first sentence is saying “Side effects won’t stop you from living your life normally”. Even more morbidly, it’s saying “Side effects won’t kill you.”
    With either of my interpretations, the second sentence – “Catching Covid might” – makes good sense.
    It might take more than punctuation to fix the ad.

  2. Thanks Paul. My first sentence didn’t actually say what I intended, and in fact contradicted what I meant to say! So I’ve deleted ‘catching COVID-19’ from the end of that sentence.
    Here was my point: COVID-19 doesn’t belong in the first sentence at all, but the advert is laid out in a way that makes it look, at first sight, as though there is only one sentence, not two.
    I agree with your interpretation of the first sentence and I agree that the second sentence is fine.

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