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103 votes

What is the effect of non-vaccinated people on vaccinated people?

Biology is rarely black or white, all or nothing. Protective immunity is generally not an on/off switch, where from the moment you're vaccinated you're infinitely resistant for the rest of your life. ...
iayork's user avatar
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78 votes

What is the effect of non-vaccinated people on vaccinated people?

Since 2000, in the United States alone, there were 16 reports of outbreaks or groups of outbreaks where the outbreak started with an initial case in an unvaccinated individual and resulted in disease ...
De Novo's user avatar
  • 8,791
53 votes

Why does vaccine development take so long?

Roni Saiba's answer does a good job of explaining what goes into current vaccine development and why it takes so much effort, but I want to directly address the question of why we can't just grow some ...
timeskull's user avatar
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53 votes
Accepted

Are the antibodies developed by differing vaccines still the same?

Due to the nature of the immune system, even people who receive the same vaccine will have a different set of antibodies. Our immune systems generate a vast number of essentially random recognition ...
jakebeal's user avatar
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45 votes

Effects of mRNA vaccines on human body processes

I can address some of the points made in the post. One point about the "artificiality": I think there's one fact that's often overlooked in the discussion of mRNA vaccines. SARS‑CoV‑2, for ...
panda-byte's user avatar
40 votes

Why does vaccine development take so long?

While the existing answers are great and cover a lot of the difficulties in vaccine development, I feel that they fail to address (or at least sufficiently emphasize) the fundamental misconception at ...
Ilmari Karonen's user avatar
39 votes
Accepted

Why did scientists state that the Omicron COVID-19 variant was a reason to get a booster?

(note: I'm simplifying things a bit here by only talking about antibodies; I don't mean to downplay other aspects of the immune response, just to keep it focused for a lay audience) Natural antibody ...
Bryan Krause's user avatar
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37 votes
Accepted

What was the breakthrough behind the “sudden” feasibility of mRNA vaccines in 2020?

Answering my own question after reading the 2018 Nature review article “mRNA vaccines — a new era in vaccinology” The resources and motivation engendered by the COVID-19 pandemic are a major factor in ...
hb20007's user avatar
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36 votes

Is there a vaccine against the plague (Yersinia pestis)?

There is little motivation right now for vaccination against plague because: Human infections with plague are fairly rare. A vaccine administered to the general populace would have to be very cheap ...
Bryan Krause's user avatar
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33 votes
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Why are vaccines for polio taken orally while vaccines for TB need to be injected?

There are different polio vaccines - one live (attenuated) vaccine which is given orally and one inactivated, which is injected. The main reason for using the live orally vaccine is that it provides ...
Chris's user avatar
  • 51.6k
32 votes

Why don't we have vaccination against all diseases caused by microbes?

Mainly cost/benefit analysis. Using vaccines has a cost, both in dollars and in risk. That cost may be very low (cheap safe vaccines, like measles vaccine), or may be relatively high (smallpox vaccine ...
iayork's user avatar
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30 votes
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What does vaccine efficacy mean?

Vaccine efficacy Pfizer's target measures for efficacy (see the study on clinicaltrials.gov) seem to be: Confirmed COVID-19 in Phase 2/3 participants without evidence of infection before vaccination ...
Bryan Krause's user avatar
  • 45.7k
29 votes

Are fully vaccinated people more likely to not get infected at all with COVID-19?

Yes, this is the effect of the vaccine. A reduction of infections of over 88%, a reduction of severe cases and death by 95% and higher. See reference 1 for the details. Data from the ReCoVAM Study ...
Chris's user avatar
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18 votes
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“The rhesus macaque is pretty much the closest thing we have to humans” — why?

Short answer: Chimpanzees are indeed closer, but perhaps...too close. Almost all invasive research on non-human great apes has halted for some time over ethical concerns. Rhesus macaques are the ...
Bryan Krause's user avatar
  • 45.7k
18 votes

Why does vaccine development take so long?

While it is true that deactivated (e.g. heat killed viruses) are used in some cases, the Pfizer, Moderna vaccines are in fact mRNA vaccines. The figure below from the Oxford website details the ...
Roni Saiba's user avatar
16 votes

Is there a vaccine against the plague (Yersinia pestis)?

There is already plague vaccine in use, which is only administered to lab workers working on Y. Pestis or people residing in areas affected with plague. (Via: https://www.cdc.gov/mmwr/preview/...
Twinkle Sheen's user avatar
14 votes

Why did scientists state that the Omicron COVID-19 variant was a reason to get a booster?

Some Clarification: Scientist were not opposed to a third dose, they were opposed to the rich country getting a third dose before we vaccinated the rest of the world. The WHO is right to call a ...
RomainL.'s user avatar
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13 votes
Accepted

Why WHO has not eliminated chicken pox like smallpox?

Eliminating a virus from the world is an immensely costly undertaking. As with most things in real life, cost vs. benefit (and feasibility) need to be taken into account. Unfortunately, there is a ...
anongoodnurse's user avatar
13 votes
Accepted

What is the motivation behind the AAAAGCAUAU GACUAAAAAA of the mRNA SARS-CoV-2 vaccine when encoding its polyadenylated ending?

To enhance stability and translation efficiency according to {1}: The 5′UTR (TEV) [8,21] and 3′ UTR (F-I) of this construct have been shown to enhance stability and translation efficiency, as has the ...
Franck Dernoncourt's user avatar
13 votes
Accepted

Do mutations occur while growing virus for preparing inactivated viral vaccine?

Very simply, mutations do occur, as they do for any cultured organism. This is a well recognized problem in many fields of biology where organisms are cultured and remains in particular a problem for ...
bob1's user avatar
  • 12.1k
12 votes

What does vaccine efficacy mean?

It means protection against the virus brought to you by the vaccination. Around 45.000 people participate in the trial; 50% of these are vaccinated with the trial vaccine and 50% receive a placebo. ...
Chris's user avatar
  • 51.6k
11 votes
Accepted

What are the difficulties/challenges against developing a coronavirus vaccine?

There are multiple challenges presented, and many of those are not limited to coronavirus vaccine. As mentioned above, it just takes time. Before a vaccine can be used in patients, clinical trials ...
Charlie's user avatar
  • 150
10 votes

Why don't we have vaccination against all diseases caused by microbes?

I would suspect that it's because not every disease caused by microbes can be treated by vaccines. For example vaccines are not as effective on microbes that cause skin infections because the ...
user40950's user avatar
  • 790
10 votes
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What goes into a vaccine placebo, typically and in the specific case of Pfizer's SARS-CoV-2 vaccine trials?

Simple answer: This vaccine trial compared their trial vaccine against saline. See the original publication by Biontech and Pfizer in the New England Journal of Medicine linked below. The relevant ...
Chris's user avatar
  • 51.6k
9 votes
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Does vaccination make the immune system "lazy"?

Contrary to many beliefs our immune system needs no "training". It is permanently active and confronted with dozens to hundreds of antigens in our food, from dust we inhale and so on. This all happens ...
Chris's user avatar
  • 51.6k
9 votes
Accepted

How harmful is aluminium?

Here is a link to the Public Health Statement for Aluminum produced by the Centers for Disease Control and Prevention (CDC) in the United States. There is much more information on the web page but ...
wanderweeer's user avatar
  • 2,733
9 votes

What is the effect of non-vaccinated people on vaccinated people?

Something which may help is a model. There is a standard model based on a key number called R₀, the basic reproductive number. This is a highly boiled up number which indicates how many uninfected ...
Cort Ammon's user avatar
  • 1,364
9 votes

Infant immunization

There are a wide variety of different kinds of vaccines. The basic principle is that the human (and more generally, jawed vertebrate) immune system can identify invaders by recognizing and responding ...
De Novo's user avatar
  • 8,791
9 votes
Accepted

Can people with AIDS/HIV be vaccinated?

Can people with AIDS/HIV be vaccinated? Yes. Immunization is an important part of the overall treatment strategy for HIV positive individuals. HIV infection is a risk factor for a number of vaccine ...
De Novo's user avatar
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