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Pfizer booster may offer important protection against Omicron variant

Pfizer has announced that a booster of its COVID-19 vaccine may improve protection against the new Omicron variant of the virus. Pfizer and its partner BioNTech said on Wednesday that while two doses of the vaccine may not be sufficient protection against the Omicron variant, lab tests showed that a booster shot increased people’s levels of antibodies capable of fighting Omicron by 25-fold. For those who have not yet received a booster, two doses should still prevent severe disease or death. Health authorities in Australia, the US and around the world have been urging those eligible to get a third dose as soon as they are able. Dr Mikael Dolsten, Pfizer’s chief scientific officer, told the Associated Press, "Go and get your third boost as soon as possible. This is comforting and a very positive message that we now have a plan that will induce immunity that is likely to protect from infection, symptomatic illness and severe disease from now across the entire winter season." US President Joe Biden said the Pfizer booster news was “very encouraging” although he cautioned, “that’s the lab report. There’s more studies going on.” The findings were announced in a press release and have not yet been subject to scientific review. Pfizer tested blood samples taken a month after a booster had been administered and found that people had levels of Omicron-neutralising antibodies that were similar to amounts proven protective against earlier variants after two doses. It’s important to note that scientists don’t yet know how big a threat the Omicron variant is. Delta remains responsible for most of the current COVID-19 cases around the world, but the Omicron variant carries an unusually large number of mutations, and scientists are working quickly to learn how easily it spreads, whether it causes more serious illness than other variants, and how resistant it might be to vaccines. Image: Jasmin Merdan

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Can COVID vaccines affect my genetic code?

The Pfizer and Moderna vaccines are set to become the mainstay of Australia’s COVID-19 vaccine rollout as the year progresses, according to the latest government projections <a href="https://www.abc.net.au/news/2021-06-23/gov-projects-little-need-for-astrazeneca-after-october-covid19/100239442">released this week</a>. <a href="https://www.health.gov.au/sites/default/files/documents/2021/06/covid-19-vaccination-covid-vaccination-allocations-horizons.pdf">From September</a>, up to an average 1.3m doses of the Pfizer vaccine plus another 125,000 doses of the yet-to-be approved Moderna vaccine are expected to be available per week. These figures are set to rise from October, as use of the AstraZeneca vaccine drops. Both the Pfizer and Moderna vaccines are mRNA vaccines, which contain tiny fragments of the genetic material known as “messenger ribonucleic acid”. And if social media is anything to go by, <a href="https://twitter.com/AJ19803/status/1334476726022385666">some people</a> are concerned these vaccines can affect their genetic code. Here’s why the chances of that happening are next to zero and some pointers to how the myth came about. Remind me, how do mRNA vaccines work? The technology used in the Pfizer and Moderna vaccines is a way of giving your cells temporary instructions to make the <a href="https://theconversation.com/revealed-the-protein-spike-that-lets-the-2019-ncov-coronavirus-pierce-and-invade-human-cells-132183">coronavirus spike protein</a>. This protein is found on the surface of SARS-CoV-2, the virus that causes COVID-19. The vaccines teach your immune system to protect you if you ever encounter the virus. The mRNA in the vaccine is taken up by the cells in your body, ending up in the liquid inside each cell known as the cytoplasm. Our cells naturally make <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3941114/">thousands of our own mRNAs</a> all the time (to code for a range of other proteins). So the vaccine mRNA is just another one. Once the vaccine mRNA is in the cytoplasm it’s used to make the SARS-CoV-2 spike protein. The vaccine mRNA is <a href="https://theconversation.com/what-is-mrna-the-messenger-molecule-thats-been-in-every-living-cell-for-billions-of-years-is-the-key-ingredient-in-some-covid-19-vaccines-158511">short-lived</a> and is rapidly broken down after it’s done its job, as happens with all your other mRNA. <a rel="noopener" href="https://images.theconversation.com/files/408058/original/file-20210624-13-1w14e5y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip" target="_blank"><img src="https://images.theconversation.com/files/408058/original/file-20210624-13-1w14e5y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" alt="Typical mammalian cell, showing different parts, such as nucleus and cytoplasm" /></a> Vaccine mRNA is in the cytoplasm and once it’s done its job, it’s broken down. Here’s why the mRNA can’t insert into your genetic code Your genetic code is made up of a different, but related, molecule to the vaccine mRNA, known as DNA, or deoxyribonucleic acid. And mRNA can’t insert itself into your DNA for two reasons. One, both molecules have a different chemistry. If mRNAs could routinely insert themselves into your DNA at random, this would play havoc with how you produce proteins. It would also scramble your genome, which is passed on to future cells and generations. Life forms that do this would not survive. That’s why life has evolved for this not to happen. The second reason is vaccine mRNA and DNA are in two different parts of the cell. Our DNA stays in the nucleus. But vaccine mRNA goes straight to the cytoplasm, never entering the nucleus. There are no transporter molecules we know of that carry mRNA into the nucleus. But aren’t there some exceptions? There are some extremely rare exceptions. One is where genetic elements, known as <a href="https://www.nature.com/scitable/topicpage/transposons-the-jumping-genes-518/">retro-transposons</a>, hijack cellular mRNA, convert it into DNA and insert that DNA back into your genetic material. This has occurred sporadically <a href="https://www.nature.com/articles/nrg2640">throughout evolution</a>, producing some ancient copies of mRNAs scattered throughout our genome, to form so-called <a href="https://www.nature.com/articles/s41576-019-0196-1">pseudogenes</a>. Some <a href="https://www.genome.gov/genetics-glossary/Retrovirus">retroviruses</a>, such as HIV, also insert their RNA into our DNA, using similar methods to retro-transposons. However, there is a vanishingly small chance of a naturally occurring retro-transposon becoming active in a cell that has just received a mRNA vaccine. There’s also a vanishingly small chance of being infected with HIV at precisely the same time as receiving the mRNA vaccine. <a href="https://images.theconversation.com/files/408059/original/file-20210624-29-gcexgw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img src="https://images.theconversation.com/files/408059/original/file-20210624-29-gcexgw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" alt="Blood sample labelled with HIV - Test" /></a> There’s a vanishingly small chance of being infected with HIV at precisely the same time as having an mRNA vaccine. Even if a retro-transposon were to become active or a virus such as HIV were present, the chances of it finding the COVID vaccine mRNA, among the tens of thousands of natural mRNAs, is extremely unlikely. That’s because vaccine mRNA is degraded within <a href="https://pubmed.ncbi.nlm.nih.gov/18797453/">several hours</a> of entering the body. Even if vaccine mRNA did become a pseudogene, it would not produce the SARS-CoV-2 virus, but just one of the viral products, the harmless spike protein. How do we actually know this? We know of no studies looking for vaccine mRNA in the DNA of people who have been vaccinated. There is no scientific basis on which to suspect this insertion has happened. However, if these studies were to be carried out, they should be relatively straightforward. That’s because we can now <a href="https://cellandbioscience.biomedcentral.com/articles/10.1186/s13578-019-0314-y">sequence DNA in single cells</a>. But in reality, it will be very hard to ever satisfy a naysayer who is convinced this genome insertion happens; they can always argue scientists need to look deeper, harder, in different people and in different cells. At some point this argument will need to be laid to rest. So how did this myth come about? <a href="https://doi.org/10.1073/pnas.2105968118">One study</a> reported evidence for coronavirus RNA integrating into the human genome in cells grown in the lab that had been infected with SARS-CoV-2. However, that paper did not look at the mRNA vaccine, lacked critical controls and <a href="https://www.biorxiv.org/content/10.1101/2021.03.05.434119v1">has</a> <a rel="noopener" href="https://doi.org/10.1128/JVI.00294-21" target="_blank">since been discredited</a>. These types of studies also need to be seen in context of the public’s wariness of genetic technology more broadly. This includes <a rel="noopener" href="https://www.nature.com/articles/nbt1099_941d" target="_blank">the public’s concerns</a> about genetically modified organisms (GMOs), for instance, over the past 20 years or so. But GMOs are different to the mRNA technology used to make COVID vaccines. Unlike GMOs, which are produced by inserting DNA into the genome, vaccine mRNA will not be in our genes or passed to the next generation. It’s broken down very quickly. In reality, mRNA technology has <a href="https://theconversation.com/3-mrna-vaccines-researchers-are-working-on-that-arent-covid-157858">all sorts of</a> <a href="https://www.wired.co.uk/article/mrna-vaccine-revolution-katalin-kariko">applications</a>, beyond vaccines, including biosecurity and sustainable agriculture. So it would be a pity for these efforts to be held back by misinformation. <a href="https://theconversation.com/profiles/archa-fox-1153308">Archa Fox</a>, Associate Professor and ARC Future Fellow, <a href="https://theconversation.com/institutions/the-university-of-western-australia-1067">The University of Western Australia</a>; <a href="https://theconversation.com/profiles/jen-martin-17007">Jen Martin</a>, Leader, Science Communication Teaching Program, <a href="https://theconversation.com/institutions/the-university-of-melbourne-722">The University of Melbourne</a>, and <a href="https://theconversation.com/profiles/traude-beilharz-1240711">Traude Beilharz</a>, Assoc Professor ARC Future Fellow, Biochemistry & Molecular Biology, Monash Biomedicine Discovery Institute, <a href="https://theconversation.com/institutions/monash-university-1065">Monash University</a> This article is republished from <a href="https://theconversation.com">The Conversation</a> under a Creative Commons license. Read the <a rel="noopener" href="https://theconversation.com/can-the-pfizer-or-moderna-mrna-vaccines-affect-my-genetic-code-162590" target="_blank">original article</a>.

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I’m over 50 and hesitant about the AstraZeneca COVID vaccine. Should I wait for Pfizer?

It’s been well documented that there’s a significant level of <a href="https://www.smh.com.au/politics/federal/older-australians-especially-older-women-most-concerned-about-covid-vaccines-20210519-p57tc4.html">vaccine hesitancy</a> in the Australian community at the moment. This appears to be a particular issue among adults over 50 concerning the AstraZeneca vaccine, for which this group is now eligible. Hesitancy over the AstraZeneca vaccine, likely to be stemming largely from the very small risk of blood clots, is leading <a href="https://www.abc.net.au/news/2021-05-21/experts-urge-over-50s-to-get-astrazeneca-covid19-vaccine/100154574">some people to ask</a>: can’t I just wait and get the Pfizer vaccine later? It didn’t help things when federal health minister Greg Hunt <a href="https://www.theguardian.com/australia-news/2021/may/20/do-not-wait-to-be-vaccinated-greg-hunt-says-after-earlier-comments-sparked-confusion">said yesterday</a> there will be enough supply of the mRNA vaccines (Pfizer and Moderna) later in the year for anyone concerned about the AstraZeneca shot. Hunt has since pedalled back on his remarks. Despite the mixed messaging, you shouldn’t wait for a Pfizer or Moderna vaccine later. There are a number of benefits to getting the AstraZeneca jab now. <h2>Thinking about the blood clot risk</h2> Thrombosis with thrombocytopenia syndrome (<a href="https://www.health.gov.au/initiatives-and-programs/covid-19-vaccines/learn-about-covid-19-vaccines/about-the-astrazeneca-covid-19-vaccine#thrombosis-with-thrombocytopenia-syndrome-tts">TTS</a>), an unusual blood clotting disorder, has been associated with the AstraZeneca vaccine. It’s important to emphasise it’s not unreasonable to have concerns about the risk of a potentially serious side effect from the AstraZeneca vaccine, or any other vaccine. The challenge is in understanding the magnitude of this risk, putting this risk into perspective, and then weighing up the risks versus the benefits before making a decision. The difficulty is your brain plays a variety of tricks on you when you try to make sense of risks like this. For example, we have a <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5773401/">tendency to perceive</a> the risks of very rare adverse outcomes (such as TTS) as being greater than they are. We also tend to be more concerned about negative consequences that may arise as a result of our actions than our inactions. That is, we’re generally <a href="https://www.frontiersin.org/articles/10.3389/fpubh.2020.614113/full">more worried</a> about a potential adverse outcome from taking a vaccine than any adverse outcome that may result from not taking it. This of course isn’t logical, but is another one of the errors we make in processing risks. In terms of assessing the risk of TTS associated with the AstraZeneca vaccine for over 50s, we’ve always known the risk is very low. At the time of writing this article the Therapeutic Goods Administration’s <a href="https://www.tga.gov.au/periodic/covid-19-vaccine-weekly-safety-report-20-05-2021">COVID-19 weekly vaccine safety report</a> reported there had been 21 confirmed cases of TTS out of about 2.1 million doses of the AstraZeneca vaccine administered. This is equivalent to one case per 100,000 vaccinations. Importantly, as we’ve got better at detecting and treating this condition, the <a href="https://www.theage.com.au/national/nsw/thousands-of-astrazeneca-shots-pile-up-in-federal-run-clinics-as-gps-wait-20210520-p57tqp.html">likelihood of severe outcomes</a> from TTS have come down considerably. So the rare risk of serious illness from this syndrome looks to be even rarer than we first thought. To put TTS into perspective, it’s also useful to note we see around <a href="https://www1.racgp.org.au/newsgp/clinical/blood-clot-death-likely-linked-to-astrazeneca-covi">50 blood clots</a> unrelated to TTS every day in Australia. <h2>Weighing the risks against the benefits</h2> The benefits of getting the AstraZeneca vaccine are considerable for over 50s, from both an individual and a community perspective. When opting to get a vaccine, you’re protecting yourself against the future risk of infection and possible severe illness. For over 50s who contract COVID the risk of severe illness and death is <a href="https://www.cdc.gov/coronavirus/2019-ncov/need-extra-precautions/older-adults.html">very real</a>. We’re also learning many people who get COVID-19 suffer with ongoing and sometimes debilitating symptoms, a phenomenon called “<a href="https://www.bhf.org.uk/informationsupport/heart-matters-magazine/news/coronavirus-and-your-health/long-covid">long COVID</a>”. Another factor which may be driving hesitancy around the AstraZeneca vaccine is the perception the Pfizer vaccine works better. But the most recent data suggest any difference in the performance of these vaccines may be smaller than we originally believed. Although phase 3 clinical trial data indicated the AstraZeneca vaccine had an efficacy of <a href="https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(20)32661-1/fulltext">around 70%</a>, new real-world data <a href="https://www.theage.com.au/world/europe/two-astrazeneca-shots-could-be-85-90-per-cent-effective-uk-data-suggests-20210521-p57ttr.html">from the United Kingdom</a> tells us it could be as much as 85%-90% effective in protecting against symptomatic COVID-19. This is positive news and not far off the 95% figure for the Pfizer vaccine seen in <a href="https://www.pfizer.com/news/press-release/press-release-detail/pfizer-and-biontech-conclude-phase-3-study-covid-19-vaccine">clinical trials</a> and in <a href="https://www.independent.co.uk/news/health/pfizer-vaccine-coronavirus-israel-data-b1842617.html">the real world</a>. And apart from effectively protecting against severe illness and death from the original strain, the AstraZeneca vaccine appears to work <a href="https://theconversation.com/im-over-50-and-can-now-get-my-covid-vaccine-is-the-astrazeneca-vaccine-safe-does-it-work-what-else-do-i-need-to-know-159814">almost as well</a> in protecting against more severe outcomes for variants of concern, such as the UK variant. Early signs also suggest the vaccine is working quite well to reduce transmission of the virus. It’s also important to understand — and this applies to all age groups — that we’re getting vaccinated for the health of the community as a whole. Although a great deal of the success or failure of the vaccination program has been framed in terms of reaching herd immunity, we don’t need to reach a certain threshold for the community to reap benefits. Every vaccine delivered makes a difference as the greater the proportion of the population vaccinated, the more difficult it is for the virus to spread. As we’ve seen in <a href="https://www.bbc.com/news/world-asia-57153195">Taiwan</a> in recent weeks, being complacent about COVID is flirting with danger. Even though we don’t have community transmission of COVID in Australia now, and we may feel safe and secure in this climate, we need to remember things could change very quickly. <h2>Get the jab</h2> There’s really no logical reason for someone over 50 to wait for an alternative to the AstraZeneca vaccine, like Pfizer or Moderna. If you do choose to wait, there’s no guarantee when any alternative might be available, and in the interim you risk leaving yourself vulnerable. By stepping up to get your vaccine as soon as you can, you protect yourself against severe COVID and make a significant contribution to putting this pandemic behind us, including getting Australia closer to opening up international borders. <hr /> Correction: this article previously referred to data from the Department of Health on the prevalence of TTS. But this was international data; the TGA figures are the most up-to-date for the Australian context.<img style="border: none !important; box-shadow: none !important; margin: 0 !important; max-height: 1px !important; max-width: 1px !important; min-height: 1px !important; min-width: 1px !important; opacity: 0 !important; outline: none !important; padding: 0 !important; text-shadow: none !important;" src="https://counter.theconversation.com/content/161283/count.gif?distributor=republish-lightbox-basic" alt="The Conversation" width="1" height="1" /> <a href="https://theconversation.com/profiles/hassan-vally-202904">Hassan Vally</a>, Associate Professor, <a href="https://theconversation.com/institutions/la-trobe-university-842">La Trobe University</a> This article is republished from <a href="https://theconversation.com">The Conversation</a> under a Creative Commons license. Read the <a href="https://theconversation.com/im-over-50-and-hesitant-about-the-astrazeneca-covid-vaccine-should-i-wait-for-pfizer-161283">original article</a>.

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Woman receives SIX doses of COVID-19 vaccine

A 23-year-old Italian woman was mistakenly given six doses of the Pfizer BioNTech COVID vaccine at the Nora hospital in Tuscany. Hospital spokeswoman Daniella Gianelli told CNN the patient was in “good health” with no underlying conditions, and was discharged on Monday, May 10 after being monitored for any adverse reactions for 24 hours. The health worker who administered the shot accidentally filled a syringe with an entire bottle of the vaccine, which contains six doses. “She saw five empty syringes and realised her mistake,” Gianelli said. The spokeswoman said doctors would continue monitoring the patient’s immune response to the “massive dose of vaccine”. The young woman was eligible for the vaccine before others in her age group because she is an intern in the hospital’s psychology department, Gianelli added, due to the Italian government’s decree making vaccination mandatory for all healthcare and pharmacy workers to protect medical staff, patients, and vulnerable people. An internal investigation has been opened, Gianelli said, adding that it was “maybe just human error, definitively not on purpose”.

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Pfizer booster may offer important protection against Omicron variant

Can COVID vaccines affect my genetic code?

I’m over 50 and hesitant about the AstraZeneca COVID vaccine. Should I wait for Pfizer?

Woman receives SIX doses of COVID-19 vaccine