The COVID-19 vaccines have been developed at break-neck speed and in some cases use new technology.
It's little wonder some of you have questions.
Since August last year, we've been collecting your queries and concerns about the coronavirus and COVID vaccines.
With the Pfizer shot rolling out in Australia this week, we've put the questions you asked most to leading experts in infectious diseases and immunisation.
From why you need a vaccine if you have a strong immune system to whether genetic vaccines can change your genome, we've got the answers.
Meet the experts
Kristine Macartney is an infectious diseases paediatrician and University of Sydney professor. She monitors the safety and effectiveness of vaccines as director of the National Centre for Immunisation Research and Surveillance (NCIRS).
Christopher Blyth is an associate professor in paediatrics at the University of Western Australia and co-director of the Wesfarmers Centre of Vaccines and Infectious Diseases. He is co-chair of Australia's peak scientific committee on immunisation, a research fellow at Telethon Kids Institute, Infectious Diseases Physician at Perth Children's Hospital and a clinical microbiologist at PathWest Laboratory Medicine.
Archa Fox is an associate professor and ARC Future Fellow at the University of Western Australia. She is a molecular biologist specialising in RNA, the genetic code behind viruses and many of the COVID-19 vaccines.
Scroll down to read all the answers, or jump ahead by clicking on the questions that interest you:
Why do I need a vaccine?
Isn't it better to risk COVID than take a new vaccine?
Professor Macartney: Though they are new, these vaccines have been so incredibly well studied. There's now more than 200 million doses that have been administered globally and tens of thousands of those were in clinical trials. So we actually know more about these vaccines than we have about some other vaccines launched in years past. It's amazing what we've been able to learn because of the mass participation of people in these trials and roll-out.
Can't I wait and see while others take it?
Professor Macartney: While a young person has a reasonable chance of not becoming critically ill with COVID-19, they certainly have a chance of passing it to others who are vulnerable and it could have serious health consequences.
The key thing here is that we will only succeed in stopping this pandemic if most of the population is vaccinated. And while some people may think "I don't need to be vaccinated, I'll rely on others", we know that if everyone joins together, taking up the safe and effective vaccines we have, that's how we can turn this into being a manageable virus rather than one wreaking havoc on our world.
We've been hoping life will be normal by 2022 — it's not quite as black and white as that. If we wish to get back to a more normal life, we quite simply need to get a lot of people protected against serious disease through vaccination.
Why can't we just immunise the vulnerable and leave others to fight COVID with their immune systems?
Professor Macartney: If we do that, this virus will continue to spread, especially to those with weaker immune systems or who are vulnerable. These people, even if they are vaccinated, will not be fully protected. They also need to rely on not meeting another person who is infected with the virus. Some people's own immune response may not respond as well to the vaccine, or if they met someone who had a very high level of virus it may overwhelm their protective response from the vaccine. The key thing here is to not meet anyone with the virus, and the way to do that is through mass vaccination, so the virus will not have anywhere to travel.
If we have a lot of people who aren't vaccinated, the virus will just continue to spread and be a risk to our families and friends. We cannot afford to have it circulating at high levels in the community.
It sometimes seems okay to say "I don't mind if I get sick", but in my experience as a clinician who looks after people in intensive care, when others feel they might have passed on that infection to a person who ends up seriously ill in hospital, it's a terrible burden to bear. People feel absolutely devastated about that — knowing they didn't do everything they could have.
Everyone knows or cares for someone who is older, or might have had treatment for cancer, or for some other reason will be vulnerable. It's so important that we think of those people, because if we're not vaccinated, we're keeping them at risk.
Dr Fox: Younger people can strengthen their immune system but as you get older your immune system is just not as good. It's just part of getting older. The only way we can protect older people and the immunocompromised is to vaccinate.
But even if every young person ate well and did exercise and had a strong immune system, if they get infected with the virus, they could still suffer from COVID-19 — some people develop long COVID, and there is mortality in all age ranges, even if you have a strong immune system. We don't yet understand why some people get really bad COVID-19 symptoms and others don't. In future we may know people's risk factors at the genetic level, but right now you're playing Russian roulette if you're going to just rely on boosting your immune system to stop getting sick.
If everybody just takes an individual stance and boosts their own immune system, that's not how vaccines work — they rely on herd immunity, it's about you protecting everyone else. The studies coming out now suggest transmission of the virus will be greatly reduced by the vaccinated.
Dr Blyth: Although we encourage people to stay healthy, there is no single way to strengthen one's immune system to make it able to combat COVID infection. The only way we're going to be able to do that is through a vaccine. So I'd encourage people to remain as healthy as possible throughout the pandemic but a key component is a vaccination. While we know some groups in particular are more susceptible to severe outcomes, COVID can affect anyone.
Is it safe?
Have approvals and testing been rushed through?
Professor Macartney: I understand people's concern given that everything has happened at pandemic speed. But it's important to remember that this has been the focus for hundreds of thousands of the world's cleverest scientists, those in regulatory authorities, and specialists in ethics and many aspects of the vaccine development and delivery process. They’ve all been working round the clock to ensure the integrity and quality of the data and the vaccines themselves. The whole scientific world and many others have turned their minds to ensuring that the quality and safety of the vaccines is paramount. Billions of dollars have been thrown at this to back that approach.
While things have gone much faster than usual, the rigour with which testing, approvals and all aspects of development have been undertaken has been of the highest standard. So many people have stopped doing the other work they do to become involved in COVID — they've turned all of their skills to support the development and manufacture. That's what's helping us know they're safe and quality products.
Dr Fox: These vaccines have not been rushed through. They are faster because there have been absolutely no delays to getting funding. As scientists, we spend so much time trying to get funding for the necessary trials and experiments to prove something works. That is the biggest delay to scientific research. Then, at every stage there were people lining up to participate in trials. Often that recruitment is difficult and a very long process. It's really those two things that removed the usual waiting times. That's why what would previously take five years took one year.
In Australia, our vaccines have had the full approval process, not emergency authorisation like in some countries. That means every bit of data that was required for approval has been provided, whereas with emergency approval they don't require quite so much data. The regulators who sit on those approval panels would've been working around the clock to scrutinise that data. In that sense there would've been a bureaucratic layer stripped away as they were able to focus on this approval, not other work.
Dr Blyth: Current technology enables us to develop vaccines much faster than previously and through collaboration between researchers and industry we've been able to do this in record time.
In addition to new technology, we did things differently this time, running trials concurrently. Traditionally, we run the three phases of clinical trials one after the other, pausing to review data between steps. But we were able to run them continuously in populations with large amounts of COVID disease, so it was faster to see if a vaccine truly worked. This was an economic risk for manufacturers and governments but not a safety risk.
The threshold for approval for these vaccines in Australia has been no different for COVID than any other vaccine. They're going through as rigorous, if not more rigorous a process than usual, given the incredible scrutiny. I have confidence they are safe and effective.
How do we know there won't be longer-term effects if we're testing short term?
Professor Macartney: It's extraordinarily rare for any vaccine to show a side effect that develops later after vaccination, such as the following week. Most side effects occur within the first few days, such as a sore arm, muscle aches or a temperature. Very few vaccines have ever been shown to have a late-onset side effect. But the regulatory authorities who've approved the vaccines have only done so on the basis of reviewing data from many thousands of people at least two months after the second dose of the vaccine. Those people are continuing to be followed.
Vaccines have been in clinical trials for nine months now where they've been given to over a quarter of a million people in those trials. More than 200 million doses of approved vaccines have also now been given worldwide and many doses have been of the two vaccines we're using in Australia. So far, we're not seeing longer-term side effects. But that doesn't stop us from continuing to monitor the safety of the vaccines. Studies are being done all around the world looking for those needle-in-a-haystack events — but we know the benefits of these vaccines are so great and the safety profile is looking excellent.
Dr Fox: The only way we can be 100 per cent sure there are no long-term problems is to monitor long-term. But when you add up all of the bits of evidence that have been gathered — studies in animals over long periods of time that show they're fine, and the ways we know the molecules and cells work, that they're broken down quickly — there's no scientific basis to believe there'll be long-term effects.
As a scientist these vaccines don't scare me at all, because I can look at all the components and know they'll either degrade or are harmless.
Every vaccine was new once. Most of us don't think too much about getting the whooping cough vaccine or diphtheria vaccine — at some point they were the new ones, but our parents or grandparents agreed to take them.
The two vaccines currently approved in Australia (the Pfizer-BioNTech and Oxford-Astrazeneca shots) are what's known as "genetic vaccines". Traditional vaccines inject a weak or inactivated copy of a virus, or a lone protein from it, to train your immune system to recognise and destroy that virus. Genetic vaccines instead give your cells instructions to make a single protein from the coronavirus themselves. As it is a single protein not a whole coronavirus particle, you can't get sick.
Genetic vaccines are new so have we had enough experience to know they're safe?
Professor Macartney: Genetic vaccines are not as new as we think. They've been under development for decades, but it's only been in recent years that they've been taken forward in licensed vaccines. For example, the vaccine that has helped stop the Ebola outbreak in Africa is a genetic vaccine and that's been pivotal to controlling the disease there. The safety of this vaccine design has been studied extensively in the laboratory as well as in many different types of animal models, and in other trials prior to Covid-19. These studies have shown this vaccine type to have a good safety record. There have also been tens of thousands of people in clinical trials who have received the different types of COVID-19 vaccines and many people vaccinated worldwide with no safety signals occurring.
I've heard the vaccines make your cells produce a foreign protein. Should I worry?
Professor Macartney: Our bodies are meeting and dealing with foreign proteins every single day in many different ways. From the moment we're born, our body is coated in foreign proteins and they make it into our nose and mouth, through our skin, into our blood, and our immune system is trained by those foreign proteins to know what the world is like and what is safe. We use foreign proteins in all vaccines to help us develop a protective response to a serious disease without having the side effects from the disease itself.
In some ways, genetic vaccines are even more natural than other vaccines because instead of injecting a foreign protein, they instruct your cells to make that protein themselves and switch on the immune system to recognise it. It's a very clever use of our own immune system. It's similar to how we're starting to treat cancer by boosting the immune system to fight cancer itself.
Do the genetic vaccines change a person's genome sequence?
Dr Blyth: One of the types of vaccines we'll be using is an mRNA vaccine [the Pfizer shot], which contains a small piece of genetic material. This is not the same as our genes (which are made up of DNA) and the vaccine has no capacity to incorporate into an individual's genes. The vaccine is a sophisticated way to get a person's cells to manufacture the key coronavirus spike protein that we need to induce immunity. It is rapidly destroyed by the body and will have no long-lasting impact on an individual's genes.
Professor Macartney: The genetic vaccines don't change a person's genome sequence.
With mRNA-based vaccines, like the Pfizer and Moderna shots, it's genetic code that degrades and disappears within moments of being used by the cells in the body. There are extensive studies that show that code is only around for an instant. In animal models, when they've tried to look for that mRNA after administering the Pfizer vaccine, they can't find it anywhere in the body. It's not the sort of substance that can stay in the body or be incorporated into human cells.
The same goes for viral vector vaccines [like the Oxford Astrazeneca shot]. They are very short-lived in the body. The genetic material is there to do the work of stimulating the immune system, then it's gone.
Do the vaccines include mercury and other heavy metals?
Dr Fox: No they don't and we know that from the published list of ingredients and components in the different vaccines. Anyone can look at the list.
Dr Blyth: Vaccines used in the Australian program do not contain mercury. The vaccines that will be used are free from preservatives and any toxic substances.
Does the vaccine make you more susceptible to HIV?
Dr Fox: This is a misunderstanding that came about after the University of Queensland vaccine trial was abandoned because it could trigger a false-positive result to an HIV test. That's because the way they made that vaccine was to piggy-back the SARS-COV-2 protein onto one little building block of HIV, not the whole virus. You can't get HIV from one isolated building block of the virus. But the HIV test would still recognise that protein and that would trigger a false positive result.
Dr Blyth: The UQ vaccine candidate produced a false-positive HIV test because a protein used in the vaccine was originally derived from the HIV virus. None of the recipients got infected with HIV because HIV is not transmitted through vaccines. A vaccine does not increase your risk of infections such as HIV, it protects against COVID-19.
Does the vaccine use cells from aborted foetuses?
Dr Fox: This is only applicable to some of the vaccines — the DNA-based vaccines like the Oxford AstraZeneca vaccine, but not the mRNA vaccines like Pfizer and Moderna.
To make the DNA vaccines you require living cells, what we call "cultured cells" or "cell lines". They're incredibly common in any research lab in the world. If you trace the history of that cultured cell line all the way back to the 1970s, the original source was donated material from an aborted foetus. That material would otherwise have been destroyed but was donated instead. They're certainly not from recently aborted foetuses.
The cells that are grown now are very different to their original source. It's the same as taking a biopsy of your skin and growing that in the lab forevermore — would you feel connected to those skin cells that are growing and growing and growing?
There is so much medical research and innovation in the last 50 years that has depended on these cultured cell lines. Without them, we would not have had the eradication of so many diseases, like Polio, for example.
Is there a miniature chip inside the vaccine that will be used to track us?
Professor Macartney: There's certainly no miniature chip in vaccines. There's so many people responsible for the manufacture and development of these vaccines that it just wouldn't be possible for that to ever occur. It's a great myth that has been catchy on social media and is intended to frighten people — it seems awful to take advantage of people with a falsehood as impossible as this feeling vulnerable in the pandemic.
Dr Fox: This is a misconception that has evolved because some researchers developing mRNA vaccines have separately done research on biotechnology that involves implants. People are putting those two things together, but that's different research from different companies for totally different products. The vaccine companies have been very transparent with publicly available lists of ingredients in their vaccines. You can read them for yourself and see there's no hydrogels, no silicone chip.
Dr Blyth: With the Pfizer vaccine, you're injecting 0.3mls of vaccine. It's a liquid injected into the arm. It does not contain any additional components and certainly nothing that could enable us to track people.
Fertility, pregnancy and breastfeeding
Do the vaccines affect fertility?
Dr Fox: There's no evidence to suggest that the vaccine affects fertility. There is also no scientific reason to suspect that the vaccines might affect fertility. It will be possible within the next year to measure if there is any drop in fertility rates because millions of people around the world have now received the vaccines.
Dr Blyth: No vaccines impact fertility and importantly, that applies to COVID vaccines. It's absolutely safe for people planning pregnancy.
Is it safe to get the vaccine if I'm pregnant?
Dr Fox: Pregnant people were not included in the phase three clinical trial — that's very common practice, for pregnant people not to be included in clinical trials of anything. The current advice is if you're not in a high-risk group, it's better to wait until we have more research. But that's only because of an absence of data, it's not based on any suggestion there is a risk. The data will come soon because all around the world people are getting vaccinated, including pregnant people, and those who want to go on and become pregnant.
Do the vaccines affect breastfeeding?
Dr Blyth: The COVID vaccines are safe for anyone breastfeeding. The recommendation is that you can receive COVID-19 vaccines at any time while breastfeeding.