There have been no clinical trials of mixing vaccines, but that hasn't stopped some countries from trying.
If you've previously recovered from Covid, you already have long-lasting immunity.
Careful, suggesting that can get you crucified in the US.
Bad analogy. What happens is that we're shooting people with .22LR (spike protein inducing mRNA) hoping it will help building immunity to bigger calibers (Covid19, not even talking about the variants).
It was bad on purpose. You can't compare the immune system to guns (like the parent does) or the Covid vaccine to seatbelts.
They prevent you from 1) having severe side effects, and 2) spreading it to others as much as if you had not encountered either.
No self-respecting immunologist would claim the COVID vaccines prevented re-infection. That's never been the claim outside of those who are ill-informed.
1. If you've previously recovered from Covid you have long term immunity.
and
2. Many many stories 1st and 2nd hand detailing reinfection (with symptoms) -- people who have definitively been infected at least twice, symptomatically.
I don't think both 1 and 2 can be true, unless "long term immunity" means something different than my layperson interpretation.
So in theory, both could be true, and also neither. We simply don't have enough data to say definitively how it really works long term, so any speculation is just that - speculation.
What medical experts can do is be realistic about what to expect from vaccines, recovery, herd immunity, etc. - which they've done quite well. It's other forms of media, "fake" experts, etc. that bolt on more guarantees to vaccines that cause an uproar when they are broken, the biggest one being that vaccines prevent re-infection.
The thing I've noticed the most throughout this pandemic is that people are incredibly short sighted. Explaining how vaccines work, and how they help to prevent spread and variant breakthrough in communities, collectively, is something that people can't seem to accept. They're too concerned with "well it doesn't affect me, so why bother?" without realizing that by getting vaccine they help to end the pandemic sooner, which does impact them directly.
Everyone is tired of the pandemic - medical staff especially - and people not getting vaccinated despite having pretty strong data right now that there are minimal-to-no side effects in the general case is ultimately prolonging the pandemic since new variants keep emerging from mutations in, presumably, unvaccinated individuals spreading shit around.
Reinfection Rates among Patients who Previously Tested Positive for COVID-19: a Retrospective Cohort Study [Mar 2021]
https://pubmed.ncbi.nlm.nih.gov/33718968/
> Of 150,325 patients, 8,845 (5.9%) tested positive and 141,480 (94.1%) tested negative prior to August 30. 1,278 (14.4%) of the positive patients were retested after 90 days, and 62 had possible reinfection. Of those, 31 (50%) were symptomatic. Of those with initial negative testing, 5,449 (3.9%) were subsequently positive and 3,191 of those (58.5%) were symptomatic. Protection offered from prior infection was 81.8% (95% confidence interval 76.6 to 85.8), and against symptomatic infection was 84.5% (95% confidence interval 77.9 to 89.1). This protection increased over time
The literature should be checked to see the different estimates of different researches.
--
Edit: those results seem consistent with my second in queue article,
Reduced Risk of Reinfection with SARS-CoV-2 After COVID-19 Vaccination — Kentucky, May–June 2021
https://www.cdc.gov/mmwr/volumes/70/wr/mm7032e1.htm
since
> being unvaccinated was associated with 2.34 times the odds of reinfection compared with being fully vaccinated
Those studies show a good amount of post infection protection, though lower than some relevant vaccines. Also duration of the protection should be factored in, and the consideration is ongoing: only a few hours ago I read material (an Axios summary) about Pfizer vs Moderna,
https://www.axios.com/pfizer-moderna-coronavirus-vaccines-ef...