Can you be injected with two different vaccines?

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Summary:

Vaccine Question.
If after a vaccine of suppose 70% efficacy is given to a person ,he will develop antibodies .
Now after a month new vaccine comes with 95% efficacy.
Can he be injected new vaccine ?
What about antibodies already in him?
Can many types of antibodies remain and have no adverse effect and do not interfere with one another as well ?
 
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  • #2
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In general, I don't think its a good idea to overload your body with multiple vaccines for the same disease. However, one should always check with your doctor about it before proceeding.

The CDC website explains more about the COVID vaccines coming out:

https://www.cdc.gov/coronavirus/2019-ncov/vaccines/about-vaccines/how-they-work.html

How COVID-19 Vaccines Work
COVID-19 vaccines help our bodies develop immunity to the virus that causes COVID-19 without us having to get the illness. Different types of vaccines work in different ways to offer protection, but with all types of vaccines, the body is left with a supply of “memory” T-lymphocytes as well as B-lymphocytes that will remember how to fight that virus in the future.
It typically takes a few weeks for the body to produce T-lymphocytes and B-lymphocytes after vaccination. Therefore, it is possible that a person could be infected with the virus that causes COVID-19 just before or just after vaccination and then get sick because the vaccine did not have enough time to provide protection.
Sometimes after vaccination, the process of building immunity can cause symptoms, such as fever. These symptoms are normal and are a sign that the body is building immunity.
You can see here that a single vaccine may give you a fever, so multiple ones for COVID may overload your body's defenses.

Recently, I had gotten in error the pneumonia vaccine part 1 after the pharmacy had confirmed I hadn't had it yet. Unfortunately, they consulted their records and not the insurance company as I did have it several months ago at a different pharmacy and forgot.

Checking with my doctor about it, they said to wait a few months before I get it again so as to avoid any possible side-effects or bad reactions to having too much vaccine in your system.

If you recall, the body processes the vaccine and learns from it how to combat the actual illness so its possible too much could induce a cytokine storm where your body over reacts to the vaccine load.

Here's more from the CDC on vaccines as given to kids:

https://www.cdc.gov/vaccinesafety/concerns/multiple-vaccines-immunity.html

They do say that certain kids vaccines for various and different diseases may be given at the same time:

https://www.cdc.gov/vaccinesafety/concerns/multiple-vaccines-immunity.html

Getting multiple vaccines at the same time has been shown to be safe.
Scientific data show that getting several vaccines at the same time does not cause any chronic health problems. A number of studies have been done to look at the effects of giving various combinations of vaccines, and when every new vaccine is licensed, it has been tested along with the vaccines already recommended for a particular aged child. The recommended vaccines have been shown to be as effective in combination as they are individually. Sometimes, certain combinations of vaccines given together can cause fever, and occasionally febrile seizures; these are temporary and do not cause any lasting damage. Based on this information, both the Advisory Committee on Immunization Practices and the American Academy of Pediatrics recommend getting all routine childhood vaccines on time.
 
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  • #3
jim mcnamara
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@jedishrfu post is very helpful.
Plus your idea of what 70% means is not an absolute 30% of the vaccinated population will get full-tilt symptoms. They will generally be abated, less intense symptoms - they fare better than those who did not get any vaccine at all. It is hypothesized that the asymptomatic covid carriers were recently exposed to a coronavirus cold. Their immune systems shutdown many symptoms when they got exposed to covid some time after their initial cold. They did not completely get rid of the virus.
 
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  • #4
Laroxe
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I'm not sure there is a clear answer to this, its not really a matter of overloading the immune system, it has evolved to deal with far more threats than most people experience & we are constantly exposed to multiple pathogens. The issue is more to do with the type of immune reaction that we develop and this varies depending on the organism and our history of exposure.

One issue is in the early responses to an antigen, our immune system is alerted and becomes far less tolerant of any potential threat and it can be a rather unforgiving beast, the greater the antigen challenge and the longer it goes on, the risk of collateral damage increases. Our immune system kills any cells it thinks is damaged or infected and it needs increasingly less evidence for this.

Of course people are aware of this and dose the vaccines appropriately. After a vaccination the immune system produces antibodies and some memory cells, the antibodies tend to fall quickly, the second dose allows the immune system to refine the type of antibodies after rapidly activating the memory cells. Two doses in quick succession interferes with this and makes the whole process less efficient and increases the risk of adverse effects, most of these would be as a result of inflammation, the more serious ones may be associated with antibodies that start attacking our own tissues.

Still, these are issues of risk and while the risks increase, serious effects remain rare.
 
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  • #5
berkeman
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I have a related question (sorry if this was addressed already in one of the other COVID threads)...

For the people who have been taking part in the clinical trials of the various vaccines, will they be able to receive and benefit from the newly approved vaccines when they are available? When are the participants in those clinical trials informed whether they received the actual vaccine or the placebo? And if they received the actual vaccine, are they informed if they have developed antibodies?

It seems like study participants who either got the placebo or the vaccine did not work would want to get the approved vaccine(s) when available. But how soon do they get informed of this information that would allow them to make that decision?
 
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  • #6
Ygggdrasil
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I have a related question (sorry if this was addressed already in one of the other COVID threads)...

For the people who have been taking part in the clinical trials of the various vaccines, will they be able to receive and benefit from the newly approved vaccines when they are available? When are the participants in those clinical trials informed whether they received the actual vaccine or the placebo? And if they received the actual vaccine, are they informed if they have developed antibodies?

It seems like study participants who either got the placebo or the vaccine did not work would want to get the approved vaccine(s) when available. But how soon do they get informed of this information that would allow them to make that decision?
Here's an article on that topic: https://www.statnews.com/2020/11/12...-vaccine-the-question-of-when-is-complicated/

Unblinding of trials and placebo patients from other trials seeking vaccination could make it harder for subsequent vaccines to gather data necessary for approval (e.g. for the more conventional recombinant protein vaccines that are being developed that could be more easily stored and distributed than the mRNA vaccines). Here are some good articles discussing the potential effects of an EUA on ongoing and future vaccine trials:
https://www.sciencemag.org/news/202...ovid-19-vaccine-could-stymie-hunt-better-ones
https://www.statnews.com/2020/10/23...emergency-authorization-of-covid-19-vaccines/
https://blogs.sciencemag.org/pipeline/archives/2020/10/21/the-vaccine-tightrope
 
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  • #7
berkeman
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Here's an article on that topic: https://www.statnews.com/2020/11/12...-vaccine-the-question-of-when-is-complicated/

Unblinding of trials and placebo patients from other trials seeking vaccination could make it harder for subsequent vaccines to gather data necessary for approva
Thanks, that's helpful (and I learned a new word, "unblinding").

But in a way, it's a disincentive for folks to participate in such trials, no? I guess I understand the scientific reasons for not wanting to unblind a study too soon, but 2 years seems a bit much...

“If you received the placebo, you may be offered the study vaccine at no cost if and when the study vaccine has been shown to be safe and that it works, but it is possible that this may not occur until 2 years after vaccination,” the J&J document reads. “This will be determined after consultation with the national health authorities in your country.”
 
  • #8
Laroxe
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Ethical guidelines for most drug trials suggest if one treatment is shown to be effective or more effective trial participants should all be offered the best treatment. The same principle should apply in vaccine trials but there may be reasons for delays, the participants should in fact have been made aware of all these issues.
I know at least one of the vaccine teams has already been talking about this issue and how to facilitate people getting access.
 
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  • #9
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To start with, for Pfizer's vaccine you are supposed to take two shots with a few week difference. With the first shot giving only limited protection, and only with the second shot will you get that 90+% efficacy.

As far as I know to require multiple shots for having higher efficacy is a pretty common solution. It's just some vaccines are not tested for this, so it's you who takes the risk and there is nobody to blame.
 
  • #10
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Yes, I've received the Zoster vaccine live seven years ago, it is about 50% effective. Two years ago, I had the recombinant zoster vaccine, Shingrix. That required two injections two months apart, but the world supply ran out before I got the second shot. Seven months later, I got the second dose. TPTB decided seven months was okay. it is rated at 90%+.
 
  • #11
Ygggdrasil
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Here's a good article addressing the original question of the thread: what happens if an individual takes two different vaccines?

https://blogs.sciencemag.org/pipeline/archives/2020/12/02/taking-two-different-vaccines

As always, there is no one single answer and a lot depends on the particular details. For polio, it seems like the two types of vaccines (oral vs injectable) are complementary and could provide stronger protection in combination. For Hepatitis A, it looks like the different available vaccines (all based on inactivated viruses) are essentially interchangeable). For pneumonia vaccines, however, there is evidence that the different vaccines interfere with each other and administration of one vaccine can lower the effectiveness of the other vaccine.

Of course, all the details are difficult to summarize succintly, so it's worth reading the entire piece to get a better idea of each of these cases and what they might tell us about the SARS-CoV-2 vaccines.
 
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  • #12
Ygggdrasil
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Thanks, that's helpful (and I learned a new word, "unblinding").

But in a way, it's a disincentive for folks to participate in such trials, no? I guess I understand the scientific reasons for not wanting to unblind a study too soon, but 2 years seems a bit much...
Ethical guidelines for most drug trials suggest if one treatment is shown to be effective or more effective trial participants should all be offered the best treatment. The same principle should apply in vaccine trials but there may be reasons for delays, the participants should in fact have been made aware of all these issues.
I know at least one of the vaccine teams has already been talking about this issue and how to facilitate people getting access.
The journal Science published a nice piece on the ethics of conducting placebo-controlled trials after an effective vaccine is approved:

COVID-19 vaccine trial ethics once we have efficacious vaccines
https://science.sciencemag.org/content/early/2020/12/02/science.abf5084.full
 
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  • #13
berkeman
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Oh my, I didn't even think of the last point...

We consider here two questions raised by this guidance: First, if a vaccine candidate is found to be safe and efficacious in a placebo-controlled trial, should the researchers continue that trial as designed? Second, should researchers continue to test other vaccine candidates using placebo-controlled trials? These two questions are especially timely given recent announcements by Pfizer and Moderna that their vaccine candidates have been found to be efficacious in preventing symptomatic COVID-19 (4, 5).
 
  • #14
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Oh my, I didn't even think of the last point...
Yes, that's an important issue to consider. As I mentioned in post #6, the two mRNA vaccines that are seeking EUAs from the FDA (the Pfizer-BioNTech vaccine and the Moderna vaccine) both require the vaccine to be stored frozen at either standard freezer conditions (-20°C for the Moderna vaccine) or ultracold conditions (-80°C for the Pfizer-BioNTech vaccine). This poses problems for distribution, especially at rural or other under-resourced areas that may not have appropriate storage conditions. Other vaccines in development have more standard storage requirements (refrigeration at 4°C) and would be a lot easier to distribute through standard vaccine distribution channels.

Furthermore, analysis of the clinical and pre-clinical data we have so far indicates that other vaccine technologies (e.g. recombinant protein vaccines) could have advantages over the mRNA vaccines with regard to lower side effects (esp. important with recent news from the UK of problems with the Pfizer vaccine in people with allergies).

The Pfizer-BioNTech and Moderna vaccines certainly look like they are very effective and should get an EUA from the FDA, but the search for better vaccines (that are more easily distributed and have fewer side effects) should still continue:
https://www.sciencemag.org/news/202...ovid-19-vaccine-could-stymie-hunt-better-ones
 
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  • #15
berkeman
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could have advantages over the mRNA vaccines with regard to lower side effects (esp. important with recent news from the UK of problems with the Pfizer vaccine in people with allergies).
Yeah, I saw that in the news:
However, the allergic reactions may have been caused by a component of Pfizer’s vaccine called polyethylene glycol, or PEG, which helps stabilise the shot and is not in other types of vaccines.
They treated the two patients quickly with epinephrine injections, and they are reported as doing well. But I wonder if all immunization locations will have epi on hand for quick administration -- I'm pretty sure that my local CVS pharmacy (where I often get my immunizations early) does not keep that at the ready...
 
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Ygggdrasil
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Yeah, I saw that in the news:

They treated the two patients quickly with epinephrine injections, and they are reported as doing well. But I wonder if all immunization locations will have epi on hand for quick administration -- I'm pretty sure that my local CVS pharmacy (where I often get my immunizations early) does not keep that at the ready...
Because of storage concerns, it's unlikely that the Pfizer vaccine would be distributed in your local CVS (does your local CVS have ultracold –80°C freezers to store the Pfizer vaccine?).

At least for the next month or two, distribution of the vaccine will be limited to healthcare workers (likely administered in a hospital or other healthcare clinic setting) or people who work or live at long term care facilities (also places that would have access to quick emergency medication).

Possibility of allergic reaction will definitely be a concern, however, if/when the vaccine becomes more widely available to the public.
 
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