Info on getting another vaccine after 2 jabs of Astra Zeneca?

July 22, 2021 1:24 PM

Partner and I got our second dose of Astra Zeneca last week in Australia (10 weeks between first and second jab). We're trying to judge the advisability and effectiveness of getting vaccinated with Pfizer or Moderna - either a single-shot booster or a full two-dose course - now that we're back in the US where we reside. All the info I can find on the Internet relates to getting first and second jabs with different vaccines.

I haven't been able to create a search query that gets me results pertaining to getting vaccinated with a different vaccine after being fully vaccinated with Astra Zeneca.

We're hoping to improve our resistance to the Delta variant, and we also have been having some difficulty in our efforts to get official vaccination verification records from Western Australia (since we're not enrolled in their health care system there). And we're not sure being vaccinated with AZ will be accepted if we end up being required to show proof of vaccination for some reason.

Any links to info about the efficacy or protocols regarding getting a different vaccine after getting two shots of Astra Zeneca would be appreciated, as well as well-formed opinions about the idea.

On preview, I've looked at the suggested similar questions and they don't really cover what I'm looking for.

posted by under_petticoat_rule to Health & Fitness (12 answers total)

Some countries are mixing vaccines as a matter of policy, though it can lead to worse post-vax symptoms as a reaction to the shot (ie the post-vax flu and soreness). Preliminary trials indicate increased efficacy, which is good. Not a doctor but it appears this has been tried in the real world and there are not major alarms in literature on risks.
posted by glaucon at 1:37 PM on July 22, 2021

If you havent, I would read Salon: I was vaccinated in a clinical trial. But officially, my COVID-19 vaccine doesn't "count", it covers some additional considerations and discussion about someone in your situation, but different vaccine. Travel restrictions, etc.
posted by TheAdamist at 2:21 PM on July 22, 2021

I can’t find the page right now because I’m on mobile, but up until very recently I was working as a team lead for a contact tracing team. AZ “counts” as being vaccinated in the USA even if it isn’t widely offered because it’s in the WHO approved list. So if you can get some sort of documentation, it would count for wherever that may apply.
posted by raccoon409 at 2:38 PM on July 22, 2021

Some European goverments are already planning and budgeting for and ordering booster doses, here in Austria most likely 9 to 12 months after the second dose.
I found a lot of info googling "covid booster shot" but the Info i found useful / saved links to is all about booster shots in the EU. In Austria, cross- vaccination is considered safe.

As far as i could find the CDC does not (yet?) recommend a booster shot. But there are also statements like this by Pfizer CEO saying booster shots may become necessary.
posted by 15L06 at 3:05 PM on July 22, 2021

I haven't re-read the CDC contraindications in a while, but I don't remember there ever being anything saying you can't or shouldn't get more than one flavor, and I have seen some countries' guidance that if you started one protocol and didn't finish or for recordkeeping reasons you don't have a fully-documented series, just get something, anything, that is available to you even if it means starting over. As others have said, cross-vaccination has been a standard procedure in other countries. Check what the CDC is saying, but maybe also check what Canada (where they were cross-vaccinating for at least a while) is saying.

I have multiple friends who got the J&J and had enough concerns about efficacy to go ahead and do-over with Pfizer or Moderna. I do not know for a fact that any of them specifically disclosed they were already vaccinated, but I know one of them was in California where I think it would pop up in the database (as I was told in line on my second Moderna day that the check-in apps would bounce you if you were already in the database as Pfizer for round 1) but that's probably not an absolutely reliable assumption.

I personally would do it, in your circumstances, out of fear that the records from Australia may not count or may cause delays/problems if we go to a more robust vaccine passport system.
posted by Lyn Never at 3:28 PM on July 22, 2021

A friend of mine is in a vaccine trial (Pfizer, I think but don't quote me on that - but I'm pretty sure it was an MRNA type vaccine). He got his first vaccination about a year ago and then recently got a booster. Point is, they are evidently testing the booster shots.
posted by flug at 3:31 PM on July 22, 2021

AZ is highly protective against hospitalisation from Delta after two doses - 92% vs 96% with Pfizer - according to UK data.

I have had two AZ doses.
posted by knapah at 3:44 PM on July 22, 2021

There was a related question yesterday.
posted by caek at 3:56 PM on July 22, 2021

We don't know yet.
posted by latkes at 5:20 PM on July 22, 2021

@flug I am also in the Pfizer clinical trial, got my vaccines about a year ago and have my next check in in about 3 weeks, I wonder if I’ll be getting a booster shot then!
posted by raccoon409 at 8:45 PM on July 22, 2021

In terms of getting vaccination records from Western Australia: You can call the GP who provided the vaccine, or log on to MyGov and get a vaccination certificate, or call the Australian Immunisation Register for a copy of the vaccination record.
posted by quercus23 at 7:44 PM on July 23, 2021

quercus23, there's been some as-yet unidentified hiccup and our MyGov/IHI records are not updating to show the vaccinated status. I'll definitely check the Australian Immunisation Register you linked.
posted by under_petticoat_rule at 5:40 PM on July 26, 2021