People have different reasons for avoiding vaccination. For some people it is because they don't understand how a vaccine works. Anything we don't understand is scary.

The idea of vaccines is to warn our bodies about specific viruses. When our bodies find something that doesn't belong, they start an immune system response. This response includes making cells and antibodies that attack the specific invader. It also includes making memory cells so that the next time the invader attacks, the response will happen sooner and be stronger.

That's why people usually only get a virus once. A vaccine is a way to introduce the body's immune system to something dangerous without making them sick.

Smallpox is a deadly disease. In the late 1700s, Edward Jenner noticed that people who got a similar disease, cowpox, didn't get smallpox. This gave him the idea of giving people cowpox on purpose. In 1796 he performed his first vaccination. (By the way, "vacca" means cow. That's where the name vaccine comes from.) The vaccinations were successful. Smallpox vaccination became common. In 1980, smallpox was declared "eradicated," which is like being extinct. There are only a very few samples of the smallpox virus kept in secure labs.

Many deadly viruses that used to be common are now rare because of vaccination.

There are different types of vaccines. Some are a weak or damaged version of the virus. Some are only parts of a virus or toxin (poison).

The newest vaccines, including the COVID-19 viruses, use part of a recipe for the virus. The recipe is in the form of DNA or RNA. The main COVID-19 ones are RNA.

The body then uses the recipe to make many copies of a small piece of the virus. The immune system "sees" the piece and has an immune response against it. It also makes memory cells. This will protect the body if an actual COVID-19 virus invades it.

No vaccine is 100% safe. Some people may have allergies or other bad reactions. That's why vaccines are tested for both how well they work (effectiveness) and how safe they are. In order to be approved, the risk from the vaccine has to be MUCH, MUCH lower than the risk of the virus. The testing so far has shown the two major vaccines to be safe and effective. As more people are vaccinated and more time passes, we will know even more.

I hope this is helpful, but people often have a tough time changing their minds. If people fight to defend their position, it gets harder to change. If we want to convince people, it can be helpful to really understand their reasoning. This means listening and asking questions without attacking. Sometimes you can agree on what evidence would cause either of you to change your minds. What do you think they find scarier than the virus?

Thanks for asking,

Thank you for this question, because I am sure that many people have the same question and even those willing to take the SARS-CoV2 (COVID19) vaccine may have some valid worries.

My suggestion is to first try to understand why your parents are hesitant to take it. My guess is you have tried this, but it can be frustrating sometimes to have the conversation. Empathy and a true effort to understand will help.

There is so much misinformation and the pace at which the pandemic is progressing and the rapid roll out of the vaccines naturally causes some anxiety. In fact, as a scientist, I'm astounded at the pace of vaccine development - prior to this, the fastest vaccine development was ~4 years! But this shows what we can do when faced with a challenge (and if resources are available) and maybe it will change the pace of other kinds of vaccine and drug development for other diseases. Although long term studies will be needed, the oversight and approvals have been carefully designed and scrutinized.

All vaccines "work" by providing a portion of the virus or a non-infective version to a person. That person's immune system recognizes it as an "invader" and begins to mount an immune response, essentially priming the system to quickly respond as soon as a real virus invades.

The Pfizer and Moderna vaccines are a "new" type - they are based on a slightly different delivery approach than a standard vaccine (this has been on the drawing boards for a while as a much-needed, faster method). But they are still pretty standard vaccines in terms of design and how they trigger the immune system to prep to fight off infection. The Astra-Zeneca vaccine, soon to roll out, is a more standard (slower to prep) type. Scientifically speaking, the main question is their effectiveness, not safety at this point.

Open conversations about COVID19 and the vaccine - and open minds willing to try and identify facts from misinformation - are desperately needed. If you can start with this kind of conversation with your family, it should help: Faced with two different "facts" (e.g. the vaccine is safe v the vaccine is not safe and will harm you) why are they willing to trust one set and not another?

No vaccine is 100% effective or 100% without side effects - as more and more people get the vaccine and as we see that the vast majority are not exhibiting side effects, I think many people who were hesitant will decide to go ahead and get the vaccine. I certainly plan to do so when it becomes available to me (quite a while yet). If not enough get vaccinated, we will not reach herd immunity and this virus will continue to wreak havoc.

The health care workers I know (personally, dozens) who have gotten it so far report nothing more than a sore arm for a day, similar to a flu shot. Misinformation and irresponsible reporting, such as news stories that highlight a vaccine mishap or adverse effects without providing context on how often they occur quickly causes people to reject the vaccine. As an example, many so-called news reports about an Alaskan health care worker who suffered a severe allergic reaction never noted that tens of thousands had been vaccinated without major incident. Instead, they focused on the one adverse reaction with no context (including that the worker had a history of allergic reactions and by way of follow up, that the worker ended up being okay after treatment). You can see how this might quickly catch on a social media wave leading to a negative view of the vaccine.

A national Kaiser Permanente survey in December revealed that only 27% of those surveyed indicated that they had some hesitancy about or will refuse getting the vaccine. But interestingly, this 27% can be better understood demographically - by age, socioeconomic background, political affiliation, and ethnicity. The long history of health care disparity in our country (and revealed so glaringly by the pandemic) has definitely contributed to this (understandably). Older folks (ages 65+) definitely want the vaccine - many are old enough to recall other diseases, notably polio and diphtheria/measles/mumps, and how the vaccines saved so many. Plus, they are in a particularly vulnerable age group.

There is an excellent, very recent Scientific American post that might help you formulate some conversation points with your family and others, focused on why some people might mistrust the vaccine or general public health measures overall.

The number of people being vaccinated climbs daily, and there are no major side effects being reported - a few allergic reactions, yes (as with any vaccine), but very, very few. This is a fact.

It would help to know why your parents do not want to get the vaccine, because those reasons may be different from the reason why we would want everyone to get vaccinated. So let me just give answers to the two main concerns and questions I could think of:

1. Is the vaccine safe?
Already before being approved, the vaccine has been given to over 10,000 people, and it will likely have been given to millions before people who are not at special risk for infection will get it. Very few severe adverse reactions have been reported, so the chance of the vaccine having a negative effect on you or your parents is very small. If you have a history of severe allergic reactions or strong reactions to vaccines, you may want to take a closer look, because people like that were excluded from the large clinical trial that led to the approval of the vaccine. Both the Pfizer and Moderna vaccines do not use a "weakend virus" as some vaccines did or do, but instead the blueprint for parts of the virus that our body makes and our immune system subsequently learns to fight. So there is no risk of getting COVID-19 from the vaccines.

Vaccines and vaccine safety are a topic that stirs up a lot of emotions and very rigid beliefs and opinions. That will make it hard to convince your parents of something that they don't already believe, because there will be lots of support for either opinion on the internet. It may be more helpful to talk to them about it with the goal of trying to understand them and explain things to them rather than the goal of changing their mind. If that discussion leads to questions, you can come back to Scienceline for an answer.

With the discussions about vaccine safety, it is important to remember that many concerns are amplified because they are about vaccines given to young children. Many of those concerns do not apply to adults, who are not developing and growing as children are.

2. Why would I get the vaccine?
The vaccine(s) appear(s) to be effective, and with that provides the fastest and safest way out of this pandemic.

The effectiveness of the vaccines, as found in the large clinical trials that led to their approval, is high. That means that if a sufficiently large percentage of people get the vaccine, the virus will not be able to spread much more if at all and the world can go back to normal. But this will not work unless enough people get the vaccine. So getting the vaccine is not just beneficial because it provides you with a high level of protection based on the results of the clinical trial (about 90%), but also because it protects everyone else (for example, people who chose to not get the vaccine because it is risky due to their history of strong allergic reactions) by reducing the spread of the virus - if enough people get the vaccine.

These answers are based on the Centers for Disease Control (CDC's) top 3 reasons for why everyone who can get vaccinated should get vaccinated:

1) The available vaccines are incredibly effective! It's important to recognize what an incredible feat this is; the CDC's most optimistic predictions at the start of the pandemic were that a vaccine might be ready by early 2021, and even that seemed unlikely. The scientists who worked on these vaccines really shattered all expectations and preconceived notions about what could be done. The Moderna and Pfizer vaccines are 94-95% effective, which is unprecedented for this kind of pathogen: read here. Sometimes incorporating emotions into a purely logical argument can be especially persuasive - we should all take pride in what these scientists have accomplished!

2) It can protect you from a deadly virus. This one seems obvious, but it's important to remind people just how serious COVID is. The BBC has been showing footage and interviews from ICUs, and it can be a really stark reminder that this is a dangerous disease to contract. Beyond being deadly, coming down with COVID can be extremely debilitating. Some survivors have suffered permanent damage to vital organs, including their heart, lungs, and brain. We still don't know how much long term damage is possible. If someone isn't worried about being in the ICU with COVID, I would argue that it's still worthwhile to get a vaccine to prevent them from coming down with a really nasty cold! Again, even for asymptomatic patients, there can be long term effects.

3) Probably most important of all, getting vaccinated will protect others by slowing the spread. You will literally be saving lives by getting vaccinated! The only way to bring the pandemic to a halt is to make sure as many people as possible are immunized. Lots of people are immuno-compromised and may not be able to get vaccinated, which makes it especially important for the rest of us to take that step. We have a responsibility to those around us, even if we're not worried about getting COVID ourselves.

SARS-CoV-2 enters the cell via the receptor angiotensin-converting enzyme 2 (ACE2). It means that once the virus is in your bloodstream, every cell that has ACE2 can be infected. We know that ACE2 is expressed in the lungs, the entire gastrointestinal tract, heart, and blood vessels. Furthermore, SARS-CoV-2 can directly enter the brain through the olfactory nerve. Indeed, we have seem injury to the lungs, cardiovascular system, and brain even after acute COVID-19 itself run its course. ( Read here for more information. Additionally, those sequelae are not limited to the serious cases only. The long-term health consequence of COVID-19 is profound.

Besides the health consequence, COVID-19 is an infectious disease. Its basic reproduction number, R0, is 3.28 to 5.7, ( source meaning that if no precaution is taken, each infected person will infect 3.28 to 5.7 people.

The current infection rate in US is around 1.3 and we still see 280,292 new cases and 4,112 death a day at the time of writing. California alone has only 13% of available ICU beds. If the healthcare system is overwhelmed, more people will die.

Since no effective lock down is enforced in the US, I cannot stress enough how important vaccination is to the control of COVID-19. Please, wear a mask, practice social distancing, vaccinate, and stop the spread.

We need to get vaccine, not just to protect ourselves, but also to protect people around us. Even if a person is strong enough to fight covid without vaccine, he/she can still carry the virus and give it to others at high risk of covid. So getting vaccine is not just a self-protection, it is more like a social responsibility to protect the entire human society, and the world.

Getting the vaccine will make you immune to the virus. That really should be the only reason needed.

There are conspiracy theories that the vaccine is unnecessary or has harmful side effects. There have been people who have suffered allergic reactions to the vaccine, but the risk from the virus (between 0.1% and 1% of the people who get COVID die) is much larger than the risk of these allergic reactions.