Pfizer/Moderna after Sonovac -- a good idea?

May 13, 2021 5:09 PM

I know someone that received Sinovac and will be returning to the US. Seeing the reports of multiple doses in the news that did not severely impact the person, safety after several months seems ok. And the difference between 60% and the 90%+ seems like a good idea. Is it? And where to look for more scientific data.
posted by sammyo to Health & Fitness (8 answers total)

It also might be worth considering the ethics of getting a second round of vaccine before the rest of the world has gotten their first.

No. This is dangerous and wrong. There is no longer a supply shortage in the US; there's a demand shortage, in fact. And a dose not taken in one place can't be sent somewhere else.
posted by dmd at 6:09 PM on May 13, 2021 [13 favorites]

There is likely very little data, bc not a lot of people have done it. I am not a person that has any more knowledge than a lay person. Having said that, I would get the Pfizer/Moderna vax. I would get the first dose and then right before I was scheduled to get the 2nd dose I would take an antibody test and see where I stood. I would then decide to go or no go on the second dose.

I also disclaim that I am the type of person who is willing to try things like this. I note that I have been to more than 150 Grateful Dead concerts and have tried all sorts of "medicines" once.

I am not sure of the upside, but I don't see a lot of downside.
posted by AugustWest at 7:58 PM on May 13, 2021 [1 favorite]

Indonesia depends mainly on sinovac, and they have had extremely good real world results, so my advice would be as your friend's fully vaccinated, there's no need to borrow anxiety about the shot they received.

Per article:

JAKARTA (BLOOMBERG) - Sinovac Biotech Ltd's vaccine is wiping out Covid-19 among health workers in Indonesia, an encouraging sign for the dozens of developing countries reliant on the controversial Chinese shot, which performed far worse than Western vaccines in clinical trials.

Indonesia tracked 25,374 health workers in capital city Jakarta for 28 days after they received their second dose and found that the vaccine protected 100 per cent of them from death and 96 per cent from hospitalisation as soon as seven days after, said Health Minister Budi Gunadi Sadikin in an interview on Tuesday (May 11). The workers were tracked until late February.
(...) The data adds to signs out of Brazil that the Sinovac shot is more effective than it proved in the testing phase, which was beset by divergent efficacy rates and questions over data transparency. Results from its biggest Phase 3 trial in Brazil put the shot known as CoronaVac's efficacy at just above 50 per cent, the lowest among all first-generation Covid-19 vaccines.


And here's a vox piece on how to understand the various reported efficacy rates which is not a straightforward comparison.
posted by cendawanita at 8:13 PM on May 13, 2021 [1 favorite]

right before I was scheduled to get the 2nd dose I would take an antibody test and see where I stood.
Antibody tests are not recommended for determining vaccine efficacy. You should just get both shots if you get one.
posted by twelve cent archie at 8:34 PM on May 13, 2021 [6 favorites]

I think when I signed up for my vaccine appointment I had to agree that I hadn't gotten a different vaccine earlier, so I'm not sure that this is technically allowed. That said, I wish that I could also do this (I got J&J because it was the first shot available to me, but I'd rather have more protection). I think there's a study happening now looking at the effectiveness of combining vaccines, but it's definitely not something that's officially recommended yet. I remember reading that some people who got the AZ vaccine in Europe were given the option to take a different vaccine after their first dose when they discovered the risk of blood clots.
posted by pinochiette at 8:42 PM on May 13, 2021

They are very specifically testing mixing traditional and mRNA vaccines for greater efficacy. If you get a traditional vaccine first, then the mRNA vaccine seems to supercharge it, but the opposite is not true. Sinovac reportedly does not work well against the Brazilian variant.

IANAD but based on what we know I'd definitely get Moderna/Pfizer when I returned to the US. (Heck, I'm getting Astra Zeneca right now and am looking at getting an mRNA vaccine once I finally get back to the US.)
posted by rednikki at 9:09 PM on May 13, 2021

In Canada because of various vaccine supply issues, we're waiting on what I think is the above linked study because its very likely we'll be in a state of "mix and match" simply out of necessity. My first shot was AstraZeneca, but it's looking like we'll have way more Pfizer by the time we're collectively on our second doses. Unless that study comes out and says its scarier than the AstraZeneca blood clots, i'm leaning towards getting the Pfizer as my second dose regardless.
posted by cgg at 10:26 PM on May 13, 2021

My wife and I received both rounds of Sinovac in March and April of 2021 and then both rounds of Pfizer in June and July of 2021. We had Sinovac first because that was the only vaccine that was available to us where we were living. We then traveled to another country that offered Pfizer so we decided to get that too.

I did as much research as I could about whether or not this was a good idea, including speaking with my primary care doctor. In the end we decided that the benefits of this plan outweighed the risks: we would get a vaccine (Sinovac) as soon as possible, and then hopefully the extra protection afforded by an mRNA vaccine (Pfizer) later on.

I experienced half a day of fatigue after the second round of Sinovac and after the second round of Pfizer. I haven't experienced any other side effects. For what it's worth, neither of us have ever tested positive for COVID-19.
posted by 6336335979884 at 12:30 AM on August 10, 2021