How Oxford-AstraZeneca's COVID-19 vaccine work - Adenovirus vector vaccine mechanism of action

[@douglasheld]

You covered the complete mechanism for a layperson! Unbelievable, thank you.

[@MedicoVisual]

You are very welcome

[@AlphaCentauri2]

I have one doubt, Can a person test false positive after covishield vaccine?

[@AlphaCentauri2]

@@sharkymoon422 But it strengthens immune system

[@rajk1872]

You’re simply awesome. Thanks for the detail presentation.

[@ArunKettimuthu]

Both the video and your answers to questions in the comments are super helpful. Thank you!

[@MedicoVisual]

So glad! Thank you so much for your appreciation

[@newbotany]

The best presentation on this subject.. Thankyou

[@reconfirmingfaith7079]

Doesn't the ability to reverses transcription mean that the mRNA vaccine could potentially convert to DNA or enter the cell nucleus?

[@realSamarthT]

Reverse transcription happens everywhere. Even if you get common flu, the cells also follow the same procedure as above, nothing super natural it is

[@Scribe3168]

How is the spike protein inserted into the modified adenovirus?

[@dr.nishantkania4511]

Beautiful work

[@Purple_Panda_54]

Thank you so much for making this comprehensive explanation! This video is exactly what I was looking for.

[@MedicoVisual]

You're very welcome!

[@lyntaylor4131]

I've just read all the comments, you don't have to reply, I see you have answered this question many times. Thank you again ❤

[@royd9186]

Perfect detailed explanation. Thank you :)

[@ralphbathan2206]

Thank you!

[@MedicoVisual]

You're welcome!

[@gmsh828]

you did an amazing job. well done brother.

[@MedicoVisual]

Thank you so much

[@sandeepsingh-zh3mf]

Do all proteins (irrespective of host or foreign) gets presented to mhc1...if yes how cd8+ identifies that they need to start immune response to says only the spike protein and not to the natural host protein

[@MedicoVisual]

Great question. I won't discuss details as it is a complex topic of immunology and need a detailed video lecture to talk about. Yes, all the proteins whether foreign or body's own are presented on to MHC1. How does CD8+ differentiate the foreign proteins from the self proteins? Well, its simple to explain (Though the mechanism is quite intricate and not fully understood.). When the T-cells [including CD8+ T cells] are developing, they undergo training within Thymus. Here the cells are "introduced" with body's self proteins. They are "trained" not to become hostile on coming across the self proteins. This process is called "Thymic schooling" or "Thymic Education". and this ability of immune system not to attack the own components of the body is called "Self-tolerane". This training system is not always perfect and, thus, sometimes the immune cells start attacking body's own components leading to diseases called "Auto-immune diseases". To visualize this, I have an analogy. Remember that Police is trained Not to attack the innocent citizens. But sometimes they end up attacking innocent people. Thats exactly what happens in auto-immune disorders.

[@doloresbecker756]

@@MedicoVisual Would this process potentially result in an autoimmune pathway, Bystander Activation of Self-Reactive T-Cells?

[@jayashreedeshpande8968]

Very nice explanation of such a otherwise complicated topic indeed

[@MedicoVisual]

Thanks a lot

[@esantone0398]

thanka for the video but its concerning this enters the nucleus of a cell… 1) are all cells in the body effected? 2) when does replication stop? 3) is there any test to see if there is damage from this? blood test? DNA test? good lord these mandates are out of hand

[@yasserfaisal7458]

What happen to the adeno DNA after it complete its process ? I'm askin because i have took a first does and im concern if it really will mix with my dna

[@yasserfaisal7458]

@@sharkymoon422 no I have asked a doctor before and he told me adeno dna supposed to break But i just wanna ask to make sure if that is true or not

[@MedicoVisual]

Adenoviral DNA will be destroyed by nucleases in your body

[@anwarsultana1776]

Very good explanation of mechanism' of action o f coviid vaccine .mashaallah

[@MedicoVisual]

Thank you

[@luzmec1]

i liked very much the video

[@kl9987]

Thank you for the detailed explanation and for answering viewers' questions. My question is: what happened to the engineered adenoviral DNA and mRNA afterwards? How long will they remain in the body? Thank You.

[@MedicoVisual]

DNA and mRNAs can only remain viable inside the cell. As soon as the vaccine transfected cell is destroyed by cytotoxic T cells, DNA and mRNAs inside it will be destroyed too.

[@rz202]

@@MedicoVisual but how long it takes for vaccine transfected cells to be destroyed ? Years?

[@MedicoVisual]

@@rz202 Not exactly sure about the timeframe. But surely not years. Perhaps few hrs to a day.

[@rz202]

@@MedicoVisual i am worried and i am physically feeling so bad right now from this astra zeneca vaccine, do you know what is thr potential long term effect it would cause? is it carcinogenic?

[@MedicoVisual]

@@rz202 It does not seem to be carcinogenic. Why are you worried?

[@suresh111100]

Thank You।

[@tapasdas6758]

Thank you Sir, for this informative video. My question is After reaching inside the nucleus of the host cell, how the Genetically modified Adenovirus DNA produces the mRna of Spike protein ? What kind of process happens inside the nucleus?

[@MedicoVisual]

Most welcome. that process is called "Transcription"

[@EduardoMartinez-pw7mu]

@@MedicoVisual Can you detail how this transcription happens? Does it uses the host DNA at any moment?

[@rwaijam]

@@EduardoMartinez-pw7mu Yes please explain I'm wondering too

[@Bafler2005]

Great video. A few questions - 1. How long on average does it take the body to start producing the spike protein from the initial dose? 2. How long does it take on average for the body to create the spike protein antigen 3. How long does it take from the initial dose for the body to create an effective enough array of defences to realistically prevent severe illness? I have read conflicting information ranging from 7 days to 22 days. Thank You

[@MedicoVisual]

Not really sure about the exact timeframe.

[@agartamahajan5663]

Thanks a lot

[@MedicoVisual]

Most welcome

[@wamiqueee]

fabulous description

[@MedicoVisual]

Thanks

[@rishikeshsharma6230]

Very nicely explained. Thanks!

[@MedicoVisual]

You are welcome!

[@glen9820]

thanks. detailed and also easy for me (non-medical person) to understand.

[@alexhunter1288]

possibility of DNA integration: When we create transgenic mice via pronuclear injection, linear copies of the transgene are randomly integrated into the genome, 25-50% of the time. Its mechanism is not well known, but the consensus is that random integration occurs by DNA repair enzymes that seek out and repair broken ends of DNA: similar to nonhomologous end-joining. The dsDNA segments in the AZ shot upon entering the nucleus, probably go through the same mechanism. If anyone sees anything wrong with this logic, could you kindly let me know? Happy to learn. Did we do sequencing to compare the genome sequences of the patients pre and post-injections to rule this out?

[@rwaijam]

Sir how does the extra recombinant dna produce mrna inside the nucleus without interfering our dna... Please kindly explain I don't understand till now I'm a medical student I'm really confused

[@lyntaylor4131]

Thank you so much for sharing... very good information!! In your opinion which of the covid vaccine options is the best?

[@lyntaylor4131]

I've just been reading all the comments, which has been very helpful also. You don't have to answer my question, I see you have answered it many times ❤

[@sandrabertelli406]

Thank you for your explanation. Your videos are perfect!

[@MedicoVisual]

Glad you like them!

[@kaustavphd]

very good presentation. in this cartoon making which software you have used?

[@MedicoVisual]

The graphics of this lecture is solely created on PowerPoint. For some lecture, I also use Blender 3D.

[@preetirai3804]

It was amazing. Request for more such videos in latest vaccine development and their efficacy.

[@MedicoVisual]

Thank you so much

[@JP-nj2sl]

Understandably clear. Thank you.

[@zishanasad]

is it the viral polymerase or mammalian polymerase that makes the RNA??

[@MedicoVisual]

Mammalian [Human] DNA Dependent RNA Polymerase

[@medtamil3388]

Super explanation bro

[@MedicoVisual]

Thanks a lot

[@bajanteen212]

Thank you Dr. Aizaz for all of your videos. Question, do you have a preference for any particular type of vaccine at the moment?

[@MedicoVisual]

I would prefer mRNA vaccine. Either Pfizer or Moderna

[@bajanteen212]

@@MedicoVisual Thanks for your response.

[@anshroutray7328]

Excellent explanation!!

[@MedicoVisual]

Thank you

[@rajagoud1623]

Excellent information

[@MedicoVisual]

Thanks

[@shree_mayuri]

Thank you maam

[@SeanRhoadesChristopher]

Thank you Dr Aizaz. How do some DNA viruses insert their DNA into our Genome, such as HSV-(1&2)?

[@MedicoVisual]

I have never heard that Herpes integrate its genome into host's DNA. If you have any reference, please share. To my knowldge, Herpes' viral genome does not integrate in the host cell genome, instead it remains as an extrachromosomal entity (journals.plos.org/plospathogens/article?id=10.1371/journal.ppat.1005834#:~:text=In%20the%20viral%20particle%2C%20HSV,remaining%20as%20an%20extrachromosomal%20entity.) *Retroviruses* however, can and do usually integrate into host's genome. The reason is that they bring their own *Integrase* enzyme with them, which helps in the process of DNA integration. Some non-retroviruses too can integrate into the host genome. I am not very clear of their mechanism. Probably it involves Non-homologous end joining (NHEJ) pathway. Even the Adenovirus Type 12 (Ad12) can integrate into Hamster's genome, but there is no substantial evidence of integration of Ad12's genome in human DNA. Fortunately, no COVID-19 vaccine based on adenovirus vector uses this type of adenovirus (Ad12), so that's an added layer of safety ;-)

[@SeanRhoadesChristopher]

@@MedicoVisual my brain hurts trying to read this, (too much jargon) Okay so HIV works as a retrovirus using RNA at first, where as HSV uses DNA but, without changing our genome, & evades detection by interference with MHC1. (studied Wikipedia page) I am not a medical student, nor am I involved in the field, but I am fascinated by how wonderfully God has made us, and the pandemic has peeked my interest. None of this is a result of natural cause but of a mind, God’s Word spoke into being.

[@SeanRhoadesChristopher]

@@MedicoVisual DNA & RNA is coded information, information is words, in the beginning God Said!

[@maoak5470]

Please see "HPV can damage genes, chromosomes directly by inserting own DNA into human DNA" www.sciencedaily.com/releases/2013/11/131107132825.htm This is thought to be the mechanism by which HPV causes cervical, oropharyngeal, and other cancers.

[@pinkpanther2729]

Dear Doctor , I never seen a video like this where I understood .. one question . Given the AstraZeneca has blood clot risks , is there any precaution we can take ( maybe a medicine or something else ) before the dose which can negate the risk of blood clotting ...

[@MedicoVisual]

Low-dose Aspirin might be helpful. But to my knowledge, there are no properly conducted clinical trials at the moment, to back up this advise.

[@philparnell757]

@@MedicoVisual how about lots of whiskey?

[@mahathirmukti6695]

Very good explanation! Very clear!

[@MedicoVisual]

Glad you liked it

[@ahmedal-obaidi8305]

Good work. One thing though, the modified DNA doesn’t enter the nucleus, rather they stay in the cytoplasm of the cells, where it gets processed by the ribosome.

[@MedicoVisual]

DNA has to be first transcribed to mRNA by DNA-dependent RNA Polymerase. This enzyme is inside the nucleus. How can it possibly be transcrbed outside the nucleus? I would love to hear more from you on this.

[@coastwalker101]

Excellent explanation thanks.

[@MedicoVisual]

You are welcome!

[@jasonespinas6866]

Wow. Very clear explanation! Thank you so much.

[@samreynolds3789]

WELL DONE !

[@wildcat1065]

Excellent explanation

[@MedicoVisual]

Glad you liked it

[@SACHINSTRUCTURE123]

Excellent Video Sir 💐💐💐🙏🏻

[@MedicoVisual]

Many many thanks

[@digitaleve2544]

is it safe AZ Vaccine? How about Blood Clots cases

[@MedicoVisual]

Vaccine induced clotting is a real phenomena but is very rare.

[@dazza9859]

Medico have you any info on Hal b27 antigen presenter v Co Vid as a well known gene v retro viruses.

[@MedicoVisual]

I supppse you are talking about HLA-B27. what is your question?

[@abdullahalmutairi8338]

Excellent work very informative and well explained.

[@MedicoVisual]

Thank you!

[@kalanajayamanna1980]

superb

[@MedicoVisual]

Thanks 🤗

[@bahp.suchiang980]

If the production of Antibodies against those spike proteins failed, OR if the Antibodies or immune cells fail to neutralize those spike proteins, how long will those spike proteins stay in the human body?

[@mmganesh6087]

great video.. interesting and explains the mechanisms well

[@mrflippy77]

A few question about adenovirus vaccines- I see a lot of medical websites saying “it does not interact with your DNA in any way” without providing a good explanation. How does it not interact with your DNA if it is a double stranded DNA that enters the nucleus? To what extent does it interact with your DNA in the nucleus, and does it get broken down by the cell and discarded? One more- where does the remaining DNA that holds the covid spike protein go? Thanks, I’m struggling to understand these vaccines and if they are actually harmless to DNA.

[@alexhunter1288]

Hi, Mr.Sacher, I agree that what you asked should be carefully investigated. I left two comments in the same video recently that are in line of your questions and you may find them relevant. If you find any leads, I'd be happy to learn about them.

[@aysec7372]

Very informative, thanks.

[@MedicoVisual]

You're welcome!

[@HeemDVD]

Thank you for the video, I was wondering are the E1 and E3 genes deleted by using siRNA by any chance?

[@MedicoVisual]

Most welcome. E1 and E3 genes are delibrately deleted. E1 is required to for Adenoviral replication. It is removed to make the vaccine replication-incmpotent E3 decreases the host's immune response. So, it must be deleted for obvious reasons.

[@indian7342]

Thanks a lot, for explaining the immune mechanism against sars-cov 2

[@MedicoVisual]

You are very welcome

[@BristolMatt]

Thank you for the video. Tbh I don't trust governments and have been very anti vaccine but your videos have helped me understand how it all works and have gone a long way in changing my mind. I think I very well might get the vaccine when my time comes and that will be because of your videos on them.

[@MedicoVisual]

I am honoured. If you have any question(s), feel free to ask.

[@jodaniels8097]

Don't have it

[@anwarulhaq535]

Funtastic.explained in a very good manner the mechanism of action of vaccine..

[@MedicoVisual]

Thank you

[@MedicoVisual]

@@christianpulido8360 Any reference for your claims ?

[@foxylady9110]

Very interesting..

[@MedicoVisual]

Thanks

[@moneypenny1267]

Put these people in prison

[@MedicoVisual]

Which people ?

[@irinakomlewa3971]

Thanks a lot for your upload. I do have 2 questions. 1.Why is it cheaper to produce the vector vaccine in compare to the mrna vaccine? 2. Are there any other advantages of the vector vaccine, besides the lower price and the longitude of the storage? Thank you

[@MedicoVisual]

Thank you for your appreciation. 1. Not really sure. Maybe because vector vaccine's technology has been around for quite some time while mRNA technology is relatively new. Plus, the Lipid Nanoparticles in mRNA vaccine contain specialized lipids that may be expensive to produce. 2. I don't think so. Personally, I prefer mRNA vaccine because it does not involve use of any foreign antigen in the form of vector and It mitigates the problem of development of immunity against vector itself on repeated dosages.

[@saxondocker3256]

What happens to the episomal DNA introduced into the nucleus? Does it stay there making spike mRNA until the cell dies?

[@destroyfrqs5859]

What happens to the genome of the adenovirus after it is transcribed to the SARS-CoV-2 Spike Protein's RNA within the nucleus of a human cell. Normally, after transcription takes place in eukaryotic cells, the RNA polymerase detaches from the DNA and the DNA is left unchanged and will be transcribed over and over again. So, would the adenovirus modified DNA be left in our nucleus to be transcribed over and over again or does it fall apart after a single (or a few) rounds of transcription. And if it remains in the cell's nucleus, what happens to it after the cell undergoes mitosis?

[@timmafee0]

Take a shot each time he says spike protein 🥃🥃🥃🥃🥃🥃🥃🥃🥃

[@sharika809]

Can you elaborate transcription process? Does it uses the host cell? Only reverse transcripted rna is used inside the adeno virus or it also uses some part of the dna of adeno virus?

[@rwaijam]

Yes we want answer

[@zehravigna4873]

Does 1 RNA correspond to 1 spike protein or many of them ? I mean, when the RNA passes through the ribosome, is the outcome 1 spike protein or many of them ?

[@MedicoVisual]

1 mRNA codes for 1 spike protein.

[@zehravigna4873]

@@MedicoVisual thank you.

[@Rick-bg7iw]

do they store the "vaccine" at such low temps to stop them from mutating in the vial?

[@MedicoVisual]

It can not mutate sponatenously. It is stored at low temperature because DNA/RNA is unstable molecule

[@MedicoVisual]

Yes DNA is much more stable thats why DNA-based vaccines including AstraZeneca and JnJ are stored at 2-8 degree C and not sub-zero temperatures.

[@zehravigna4873]

What is the enzym which converts the DNA of the virus to RNA ? Thank you.

[@MedicoVisual]

DNA-directed RNA polymerase type II

[@zehravigna4873]

@@MedicoVisual Thank you.

[@zehravigna4873]

When they inject the adenovirus vaccin, this vaccins contains also some genetic code (without replication enzyme of course) of the chempanzee DNA. Can we say that we also therefore develop an immunity for the chempanzee adenovirus as well as the coronovirus ?

[@MedicoVisual]

Yes, thats called "Vector immunity". Its a problem with this type of vaccine. I speculate it to be the reason of lower effectiveness of Oxford vaccine than the Pfizer's and Moderna's

[@zehravigna4873]

@@MedicoVisual By means of adenovirus vaccins, it is therefore great to develop an immunity for both chempanzee virus and coronavirus. Why are you saying that Oxford vaccine has lower effectiveness ? Why developing an immunity to the chempanzee virus should lower the effectiveness of the Oxford vaccine ?

[@zehravigna4873]

@@christianpulido8360 Yes, but they use it also as a vaccine such as Astrazeneca/Oxford vaccine.

[@zehravigna4873]

@@christianpulido8360 Yes, The Oxford/AstraZeneca vaccine is a viral vector vaccine and uses an adenovirus which is originally derived from chimpanzees.

[@MedicoVisual]

@@christianpulido8360 No, its not

[@J-MKN]

What happens to the cells that get the vaccine DNA injected into their nucleus? Does the body get rid of those cells or do we keep those modified cells in our body forever?

[@MedicoVisual]

It is destroyed by the immune system.

[@J-MKN]

@@MedicoVisual & are there any vaccines in the past that have penetrated our cells' nuclei?

[@MedicoVisual]

@@J-MKN Ebola vaccines work on a similar mechanism

[@MedicoVisual]

To me, both vaccines appear to be safe, but I agree with you, mRNA vaccines are extra-safe in this regard. They never penetrate the nucleus.

[@Fellwich]

I'm an undergraduate biology student from Germany and this is what I needed to understand how the vaccine I'm going to take works. Thank you for explaining this! I wish my faculty would have offered a special lecture to educate us about the coronavirus vaccines. :)

[@MedicoVisual]

Thank you for your appreciation

[@AlphaCentauri2]

I have one doubt, Can a person test false positive after covishield vaccine?

[@MedicoVisual]

@@AlphaCentauri2 PCR test for COVID-19 detects RNA of Sars-CoV-2. Since this vaccine does not contain Sars-CoV-2's RNA, Its very unlikely that it may lead to false positive test.. However if some antigen test detects spike protein, that test may be falsely positive for very short span of time.

[@AlphaCentauri2]

@@MedicoVisual So can I conclude that rt pcr test will not test false positive after covishield vaccine. I am asking this for knowledge purpose. One of my relative is mbbs doctor, he was saying saying that rt pcr can sometimes test false positive after covishield vaccine. So is he wrong? I am in confusion. Please confirm.

[@MedicoVisual]

@@AlphaCentauri2 I disagree with that doctor. Vaccine can not yield "false" positive PCR result.

[@Arka913]

I've just taken the second dose of Covishield(Indian version of AstraZeneca).. I didn't have any side effects whatsoever in case of both doses.. but as you say if my body has become immune to the vector(chimpanzee adenovirus) then my immune system might be compromised against coronavirus. Now my question is can I in future take the mRNA vaccine to be safe and will I be allowed to do so??.. thank you.. And another question.. what are variants of a virus??

[@MedicoVisual]

"if my body has become immune to the vector(chimpanzee adenovirus) then my immune system might be compromised against coronavirus." No, when your body becomes immune to the chimpanzee vector, it won't affect your immunity against coronavirus in any way. It only means that if the exact same vector is used again to drop another vaccine, that vaccine might fail to trigger a strong immune response. "what are variants of a virus??" Variants develop when there are certain changes in the genetic code of the virus that make it slightly different from the original virus. Kinda like siblings.

[@tmssp]

Love your explanations doc. I just have 1 question, why isn't the adenovirus able to infect humans anymore and cause disease? How can we be sure that the engineered element of the virus' DNA can't cause this adenovirus to become a cause of disease once more? What's the mechanism that stopped it being harmful in the first place and could that have occurred, due to the spike protein it once had, not working in the human body any longer? Or is that not how it works? Sorry... Layman, just looking at all angles! 😁

[@MedicoVisual]

No need to be sorry. It is a great question actually. To understand this, let's understand how a virus generally works. When a virus enters the cell, it hijacks the protein-synthesizing machinery of the cell. So, rather than creating essential cellular proteins, the hijacked or infected cell starts creating viral proteins and proceeds to make copies of viral DNA/RNA. In this way, a lot of viral particles are created by the infected cell. Or you can, the infected cell has now become virus-generation-factory. By the way, that's the reason why a virus can not reproduce outside the host's body. It needs to hijack the cell to make copies of itself. So, as more and more virus particles come out of the cell, they continue to infect more neighboring cells. In this way, a large number of cells become virus-generating-factories. If the immune system never intervenes, this vicious cycle will keep on running. But fortunately, it alarms the immune system. It sets the immune system on fire. Well, not literally on fire. I mean the immune system becomes really annoyed and overwhelmed that it starts killing those hijacked cells (virus-generating-factories). This leads to the loss of a lot of cells in very little time and that leads to symptoms of the disease. This is a necessary evil for the immune system. Ideally, an immune response should kick an as soon as a very few cells are infected and thus nipping the problem in the bud. In a nutshell, it's usually the immune system that causes much damage rather than the virus itself. However, some degree of damage is mediated directly by the virus itself depending upon the type of virus. If we make a virus replication-incompetent, it renders the virus incapable to make copies of itself. This means, it can not turn the infected cell into virus-generation-factory, so as to say. A few cells that are "infected" by the vaccine particles will be lost and that's it. They will be re-generated in a matter of few hours. Loss of these cells will cause redness and injection site pain that will subside within a day or so.

[@tmssp]

Thank you@@MedicoVisual, I think I get it? So what you're saying is, in a nutshell, the actual part of the virus that causes the replication has been removed, so it's unable to make those virus creating factories, as you put it (nice analogy by the way) and cause disease. So now, all it is doing, is just creating a signpost for the immune system to identify, if it comes into contact with it in the future? Is that the general, nuts and bolts of it?

[@MedicoVisual]

@@tmssp Yes, you got it right.

[@tmssp]

Cool! Thank you@@MedicoVisual, for your very helpful and easy to grasp explanation 😁

[@MedicoVisual]

@@tmssp You are most welcome

[@jroswald]

Should we not be assessing adenovirus based vaccines more holistically with regard to safety and efficacy? Specifically, given that the J & J based jab is a single dose vaccine, is there any biological reason to expect the AZ (or the Gam or Sino) vaccine not to be effective with a single dose regime? Surely one problem with the Adeno based approach is that immunity is built up anyway to a second injection of the same vaccine. Also, if the increased risk of central thrombosis with the AZ vaccine is confirmed, shouldnt we expect this to be a feature of all adenovirus based vaccines? Seems it should to me. Perhaps strategies should change so that a different adeno vaccine is given for the booster or variant vaccination. We should have enough real world data to know whether a booster of the same vaccine provides any significant extra protection or not, or whether a booster should be given with a different vaccine. the problem to me seems to be that we are over-relying on the modalities of the clinical trials and their (restricted) data and we are not looking at emerging real world data enough.

[@gusrpg6669]

very good explanation of the long covid

[@dasolim886]

I am just curious. In theory and based on the data, dna vaccine seems alright too. But what are some factors that are causing concenrs for people who are worried about DNA vaccines? I heard that many people still prefer the mRNA vaccines, is it because of mRNA vaccines do not have to inject foreign antigen into your body? Also, what are some side effects that can come along with dna vaccine? One last question, isnt dna vaccine effective because we have never been introduced to adenovirus? I heard that dna vaccine requires two shots, why is that? Wouldnt the first exposure kind of prevent the second shot from being effective?

[@MedicoVisual]

I too prefer the mRNA vaccine. Reason: 1. Chimpanzae's Adenovirus antigens are being injected. Which isn't much of an issue for most people. But I would personally prefer a vaccine with as minimum antigens as possible. [Fewer antigens = Less chance of molecular mimicry] 2. On this basis of official data, mRNA vaccines are way more effective than the Oxford vaccine. 3. Although there is almost no possibility that Adenovirus vector vaccine may bother our DNA. mRNA vaccine is extra-safe in this regard, as mRNA doesn't even enter the nucleus. Regarding safety, both types of vaccines appear to be safe in most people. Yes, there have been some reports of side effects with both vaccines like Idiopathic Thrombocytopenia and Anaphylaxis in very few people out of millions with mRNA vaccine and Transverse myelitis and Multiple sclerosis with Oxford vaccine. But remember no drug/vaccine is safe in 100% of the population. You are correct about the last question. Oxford vaccine reported a better immune response in trial participants who were given half, first dose and about a month later, a full, second dose, as compared to those who got full dose both the times. My hypothesis for this result is that the first full dose results in mounting of a strong immune response against the vector i.e. Adenovirus which renders the 2nd dose partially less effective. When the half dose was given first time, the immune response against the vector might have been nominal enough to allow the second dose to remain effective. To counter this problem, Russia's Sputnik V vaccine uses two different types of Adenoviruses for both doses.

[@dasolim886]

@@MedicoVisual Thank you so much!!

[@alexhunter1288]

Q1. Will these DNA fragments be maintained as an extrachromosomal array or will they be eventually integrated into the human genome, which we know occurs sometimes, especially as our genomes have lots of viral genomes anyways from our ancestors. Q2. If they go into the germ line cells, will the transgene propagate between generations? My understanding is that adenovirus is good at affecting a wide array of cell types.

[@ezzovonachalm7534]

The B.1.1.529 cov- variant of super- concern just appeared ( November 2021) in South Africa will SOON show HOW efficacious our vaccines are !

[@leonleung5459]

Do you think AstraZeneca/Johnson or Pfizer/Moderna mrna type has more room for error to cause problems in humans? Based on the single fact alone of the fact that the materials go into the nucleus, it seems like AstraZeneca/Johnson seems like an error would cause a bigger issue. Do you agree? What do you think? Thanks!!

[@MedicoVisual]

I agree with you. Pfizer/Moderna's vaccine appears to be more safe in this regard as mRNA does not even enter the nucleus.

[@AlphaCentauri2]

I have one doubt, Can a person test false positive after covishield vaccine?

[@aluri1997]

Madam, nice presentation. Vector DNA integration with DNA of Corona ; rna converted to DNA ; then again this DNA , transcribed to mrna in the nucleus . 👍👍👍👍

[@wilburdesouza]

I couldn't help but laugh at coxsackievirus😂. Great lecture though!

[@MedicoVisual]

Thanks! 😃

[@ilakkiyailakkiya3452]

Is it supports HIV also

[@MedicoVisual]

it has nothing to do with HIV

[@ilakkiyailakkiya3452]

Y

[@Rick-bg7iw]

this seem more like some sort of immune therapy than a vaccine

[@MedicoVisual]

Indeed.

[@athomas9070]

They changed the definition of vaccine in fact to cover this. By old definition it's not a vaccine.

[@_cimone]

THANK YOU SO MUCH. !!!! I am Currently sitting here with a fever from the AZ Vaccine and absolutely nerding out on what is happening in my body.

[@lyntaylor4131]

Hope you weren't unwell for long...how long did you have those symptoms?

[@nonyabeezwax8693]

Do not get the arm candy they are all meant to remove you

[@onezone8865]

How are we sure that the DNA from the vaccine doesn't mix with the human DNA? I'm not very informed in biology so you have to excuse my stupidity here but as far as my high school biology takes me the DNA should both mix right when it enters the nucleus?

[@MedicoVisual]

It isn't stupid at all. It's a very important question. Before I answer this question, an important disclaimer here, that in science there is nothing like "absolutely sure". Everything is based on some evidence. Any new evidence may refute previously presumed information. With the being said, currently, there is no substantial evidence that Adenoviruses, other than Adenovirus type 12, can integrate their genome into mammalian DNA. Adenovirus Type 12 can integrate its genome into hamster DNA, but not in human DNA, although the mechanism is not clear. The cherry on top, no adenovirus vector vaccine against COVID-19 is using Adenovirus 12 as a vector, so that's another layer of safety measure being taken. Retroviruses on the other hand have been known to integrate their genome into Human DNA as a part of their life cycle. So they must not be used as a vector. They do so because they have their own reverse transcriptase enzyme that converts their RNA into DNA. They, then use their "own" Integrase enzyme to integrate this DNA into human DNA. However, adenoviruses do not have such mechanism, so it's least likely that they will ever be able to integrate their DNA with human DNA.

[@TheToadley]

@@MedicoVisual Hi, thank you for the great video on this subject. I'm new to this and you've helped me a lot in understanding how things work. I would like to ask a question sort of related to this comment. In a hypothetical scenario where adenovirus vector dna did integrate with our own cell's dna within the nucleus, would this then cause that cell (before being destroyed) to produce other copies of itself but with covid protein spikes, thus becoming targets to our immune system? If such was a possible occurance, wouldn't that be observed already during the clinical trials rather than in long term future? Or would the hypothetical concern be that the integrated dna could remain dormant in cell copies and something could activate it later on?

[@MedicoVisual]

Integrating into DNA isn't a problem if such cell gets destroyed by immune system or spantenously dies due to DNA damage. Fortunately, most of the times thats exactly what happens. Cell die, before it can replicate further and trigger carcinogenesis. However in immunocompromised people the story may be different, the cell with integrated DNA may persist and continue to divide and may lead to cancer. Few years back, scientists tried to treat the SCID, a genetic disease causing immunocomprimised state, by using Retroviral vector based gene therapy, the trial participents recovered from SCID but sadly 3 out 17 patients developed leukemia. [Ref: onlinelibrary.wiley.com/doi/full/10.1002/path.1896]

[@zehravigna4873]

@@MedicoVisual "Integrating into DNA isn't a problem if such cell gets destroyed by immune system or spantenously dies due to DNA damage." When these damaged cells get destroyed by our immune system, is it called "apoptosis" ?

[@MedicoVisual]

@@zehravigna4873 Apoptosis is simply programmed cell death. Apoptosis may be induced by immune system, specifically by cytotoxic T cell or by some inherent cellular mechanism trigerred after some component of cell is damaged e.g. Mitochondria or DNA. Cells can also undergo apoptosis when there natural lifetime period is elasped

[@tamilselvan3158]

Very good presentation👏👏👏

[@MedicoVisual]

Thanks a lot

[@HHedda]

Thanks but no thanks!

[@MedicoVisual]

Why not?

[@gusrpg6669]

poison

[@chinrairo7379]

Thank you so much.

[@MedicoVisual]

You're welcome!