Mixing increases reports of mild side-effects

[TruelyWonder]

Adults are more likely to report mild and moderate side-effects after mixing doses of the AstraZeneca and Pfizer Covid vaccines, a study indicates.

www.bbc.com/news/health-57075503

@Cookerhood

ComCov2 is in people who have already had their first vaccine (to speed up the results) At 8-12 weeks: If they had AZ first they get either AZ, Moderna or Novavax second, if they had Pfizer first they get either Pfizer, Moderna or Novavax second, so no mixing of AZ & Pfizer (because that's already being done, so a waste of volunteers). For those that like anecdata, I had AZ first with some unpleasant side effects, but nothing major (bad headache, myalgia, temperature, insomnia, sore arm), similar but milder after the second unknown dose.

Interesting. I’m going to speculate AZ or Novavax for your second dose then. 🙂 Novavax is supposed to be quite gentle.

I'm back & forth over it! Why not Moderna?

Not sure how relevant this is until we know how the mixing affects the incidence of blood clots. I’d happily take worse symptoms like fever and headache for a few days post vaccine if it meant a lower risk of a blood clot.

@Cookerhood

I'm back & forth over it! Why not Moderna?

Just based on the initial results it seems if you got Pfizer following AZ you are likely to have had a stronger reaction to the booster. But it doesn’t necessarily follow that Moderna and Pfizer will act the same just because they’re both mRNA, and the initial results were after a 4 week boost, not 12.

Pure speculation, in other words. 🙂

@Goodasgolden

Not sure how relevant this is until we know how the mixing affects the incidence of blood clots. I’d happily take worse symptoms like fever and headache for a few days post vaccine if it meant a lower risk of a blood clot.

The study is really too small to assess the impact on clotting incidence. The additional side effects seen in these first results would make me very wary of mixing and having AZ as the second, booster dose, so I hope the authorities here never go there.

@TruelyWonder

I think the clue there is it says 28 -34 days post vaccine and is talking about one dose.

We already know AZ takes longer to build up antibodies. That a gap of 8 to 12 weeks works best. So research wise this is old news really.

I am actually really impressed that AZ was found to have such a high percentage so early on. That is marvellous news. So thnk you for posting that.

I mean one age group only 3% between them and the other age group only 7% between them. When AZ is at its weakest moment one a month after first dose. That just goes to how amazing these vaccines are❤

Most of that statement is wrong.

Where on earth did you get the idea that the AZ vaccine is at its weakest a month after the first dose?

BOTH Pfizer and AZ are shown to have very strong efficacy FROM 14 days after FIRST dose (ONS studies).

I know that. I was addressing another poster. Who seems to think the AZ data is bad in some way. When we now it is good and gets even better with a longer gap between doses.