COVID-19 vaccines are not going to give you COVID-19

Edward Nirenberg
2 min readNov 26, 2020


A short update: This article discusses that people ought to be warned that they might have some strong immune responses when they get their COVID-19 vaccines, and that could be uncomfortable. Here’s the deal:

These vaccines are coming, and that’s great! But you should be aware that the immune response they produce is somewhat intense (if they didn’t do this they couldn’t be effective). You might get a fever or have joint pains or get a headache, especially after the second dose, and it might be disruptive to your normal routine for a day or two. That’s normal and indicates your immune system is functioning as it should be. On the other hand, you might not get these effects. But, that doesn’t necessarily mean you aren’t protected, so don’t worry.

In any case, these are much better than getting COVID-19, so please don’t be discouraged by this.

If flu is any precedent, once the vaccine is rolled out, you will hear plenty of reports that someone got a vaccine for COVID-19 and it gave them COVID-19. This is impossible.

The mRNA vaccines (Pfizer and Moderna) contain only the spike protein (antibodies directed against the protein will prevent the virus from being able to enter cells and cause disease). There’s no chance here that they can give you COVID-19. The instructions just aren’t there. There’s no virus being made.

The vectored vaccines use a different virus (a vector) that just has the spike protein stuck to their surface which the immune system will respond against. Many of these viruses have mutations that make them incapable of replicating, including the Oxford/AZ vaccine which will likely have approval soonish.

What’s actually happening here is:

  • The person in question got the vaccine and had a significant immune response with those unpleasant side effects and concluded that they have COVID-19.
  • The patient contracted COVID-19 before they got the vaccine and the vaccine failed to provide adequate protection to prevent them from getting the disease (possible given the long incubation period, especially if there was only time for one dose).
  • The person got the vaccine and generated a protective response but contracted some unrelated infection that they decided was COVID-19

This is the same as what we see with influenza. Influenza vaccines come in two forms:

  • You can get a nasal spray vaccine which contains a live virus but it has been adapted to grow very poorly in humans and cannot cause disease. If somehow this virus was found to be the cause of a true case of influenza, it would reflect a SEVERE immunodeficiency on the part of the patient.
  • Alternatively, the injection vaccine contains no live flu virus. It contains the major proteins that the immune system responds against from flu but there is no intact virus in there.

You can’t get flu from the flu vaccine.

You won’t be able to get COVID-19 from a COVID-19 vaccine.

Hope that makes sense. Stay safe everyone!



Edward Nirenberg

I write about vaccines here. You can find me on Twitter @enirenberg and at (where I publish the same content without a paywall)