Answering common questions about the new SARS-CoV2 vaccines
Who am I and what do I even know about science? I’m a PhD student of biomedical science at the Hebrew University faculty of medicine. I do a bit of cloning here, virus production there, with some brain dissections sprinkled in.
Part 1: Types of vaccines and how they work
a) mRNA
First of all, what even is mRNA?
Cell biology 101 lesson: The cell has two main compartments- the cell nucleus, which contains the DNA, and the cytoplasm, which is everything outside the nucleus, meaning all the cellular machinery and organelles. DNA in the cell nucleus is copied into mRNA, which then exits the cell nucleus into the cytoplasm and is made there into protein.
mRNA vaccines are composed of mRNA containing the gene for the spike protein of the SARS-Cov2 virus. It enters the cell and is made into the spike protein in the cytoplasm of the cell. The cells then disassemble the proteins (called antigens), attach them to the outside of the cell membrane, and present them to immune cells. This leads to the production of neutralizing antibodies against the antigen, and memory cells against the antigen. The next time the immune cells run into that particular antigen, the memory cells immediately come out of retirement and mount an immune response. The mRNA is quickly degraded in the cytoplasm (median half-life of human mRNA is about 10h(1)) and never enters the cell nucleus.
Vaccines include: Pfizer-BioNTech, Moderna
b) Viral vector
The gene for the coronavirus spike protein is attached to a harmless virus (commonly an adenovirus) and the virus infects the body’s cells and translates the gene for the spike protein in the cell. Just like the mRNA virus, the spike protein is then presented on the cell membrane to activate the immune system. The virus is harmless and lacks the genes for replication and is therefore unable to spread throughout the body.
Vaccines include: Oxford-AstraZeneca, Sputnik V, Johnson & Johnson
c) Attenuated/killed virus
Classic vaccine technology where the virus is either weakened or killed and then injected into the body.
Vaccines include: Sinopharm, Sinovac
d) Lab made viral protein subunit
The spike protein is created in a lab, purified, and injected into the body. The immune cells recognize it as foreign, and mount an immune response.
Vaccines include: Novavax
Part 2: Common questions that have been raised about the new mRNA vaccines
1) Why would I want to inject foreign compounds into my body?
mRNA is literally the least foreign object you could inject into your body. Your body makes RNA 24/7 and without it you would die. If RNA was dangerous or carcinogenic, we would all be dead.
2) Why should I be vaccinated with a vaccine that was tested and approved so quickly?
The longest testing stage of a vaccine is the phase III trials, where researchers have to wait long enough for the trial participants to be exposed to the virus naturally (since they don’t test participants by infecting them with viruses). During a global pandemic, this waiting time is much, much shorter since the rate of exposure is drastically higher than other naturally occurring viruses, such as HPV or hepatitis. Obviously, the bureaucracy usually involved in anything government related was expedited. In all cases except for the Sputnik V vaccine, in which Russia volunteered its entire population for Phase III trials, all testing phases and clinical trials were performed properly and the safety profile was analyzed and found acceptable. As a side point, can you imagine how long it would take to test a rabies vaccine by waiting until enough participants are bitten by a rabid raccoon?
For more information on vaccine approval, this is a great article that explains why vaccines usually take so long to be approved, and why the process was so much shorter for the coronavirus vaccines.
https://science.thewire.in/health/coronavirus-vaccines-clinical-trials/
mRNA vaccines have been studied in humans since at least 2011. This is not as new a technology as people seem to think. It’s currently in development for rabies, cancer, HIV, and more(2). In fact, Moderna has been researching mRNA Zika and Influenza vaccines since at least 2017. No one has died from any of these vaccines(3).
In fact, mRNA vaccines do not have the safety concerns of contamination like other types of vaccines, because there’s no virus used, or toxic chemicals (such as formaldehyde, which is used in attenuated virus vaccines), and no need for cell cultures which can breed contamination by other microorganisms. The short manufacturing time of mRNA vaccines also allows little opportunity for contamination(3).
3) Do mRNA vaccines have long term effects?
Vaccines as a rule don’t have long term side effects. Side effects from dangerous or defective vaccines generally occur up to 2 months after vaccination. Vaccinations that have been approved for use in the general population are very rarely recalled, and those that have been recalled were due to side effects that occurred within 2 months of vaccination.
A rotavirus vaccine called Rotashield was recalled in the US in the 90’s after it was found to cause small intestinal blockages in small percentage of people. In 2010, a flu vaccine (Fluvax) was withdrawn after it was found to increase risk of febrile seizures in children under the age of 5. However, side effects of both vaccines occurred within several weeks of vaccination(4).
To read more about vaccine recalls and safety concerns (hint, most of the safety concerns investigated were found not to be vaccine related): https://www.cdc.gov/vaccinesafety/concerns/concerns-history.html
In short, the mRNA is injected into the body, translated into the spike protein, induces an immune response that generally doesn’t last more than several days, and is quickly degraded in the cells. The vaccine doesn’t stick around in the body to cause long term effects, and the immune response simulates the immune response that occurs after viral infection, without the damage caused by the actual virus. Fears about unknown long term vaccine effects are unfounded, since we are way past the 2 month mark with these vaccines.
4) How many people have died from being vaccinated?
None. Many media headlines have grabbed attention with claims such as “Spain: ‘At least seven die at care home after getting Pfizer COVID-19 jab’” and “Norway: ’30 people died in nursing homes following the coronavirus vaccine.’” After investigation of the events in Spain, they found that all 9 deaths were ironically COVID19 related deaths and that there had been an outbreak at the facility during the scheduled vaccination period. In the second case, 33 elderly people out of 55,000 people that had received a vaccination died shortly after vaccination. According to the Norwegian Institute of Public Health, the order of priority of vaccination is first- nursing home residents, second- age 85+, third- ages 75–84, fourth- ages 65–74 years and people with conditions that make them high risk. So let’s assume that the 55,000 people vaccinated were the country’s oldest and frailest population. In Norway, around 45 elderly people die a day in care homes. When you vaccinate a lot of old people, some of them are going to die just because they’re old.
For more fact checking info, check out:
https://www.dw.com/en/fact-check-no-links-found-between-vaccination-and-deaths/a-56458746
5) Why is it important to get vaccinated?
Vaccination can only stop a pandemic if it’s carried out at a population level. Vaccination can prevent people from getting seriously ill and reduce transmissibility from a vaccinated individual. For now. The problem with using vaccination as a personal solution is the rate of mutation of the coronavirus. With every new host it infects, there is a chance of mutation. And while the rate of mutation is lower than that of the influenza virus(5), the higher rate of spread and significantly larger number of hosts (and the fact that there is no off season, unlike the flu) dramatically increases the chance of a new, more virulent mutation. The 3 new variants first identified in the UK, South Africa, and Brazil are reported to be more transmissible than the original version(6). There are now reports out of NY as well about a another new, more virulent strain(7,8). The current vaccines are reported to be somewhat less effective, at least against the South African strain(9). More and more people are becoming wary of vaccines due to misinformation and conspiracy theories. In one study, only 54% of French adults said that they planned on getting vaccinated(10). This means that the coronavirus will continue running rampant in the unvaccinated population, mutating into more virulent, transmissible strains, and becoming more and more impervious against existing vaccines and antibodies from previous infections. So the most vulnerable populations, like the elderly, immunosuppressed, and those with health conditions, who have been vaccinated to protect themselves from a very high chance of COVID related complications and possible death will no longer have effective protection. We can keep updating the vaccines for every new strain that emerges, but that would require be vaccinated on a much more frequent basis than anybody wants.
So is it worth risking peoples lives (and livelihoods) because of your fears of getting vaccinated? Is it worth waiting until enough time has passed to prove to yourself that there are no unexpected side effects before getting vaccinated? How long until you’re completely satisfied that it’s safe? 5 years? 10 years? How many people will have died by then? Is it worth taking the risk that it won’t be you? That if you get sick, you’ll have a relatively easy illness with no serious complications? What about the second time you get sick? Or the third? Are you willing to risk your parents? Your loved ones? Your friends? What possible long term side effect that we don’t know about yet is worth risking all of that?
Sources:
1. Yang E, van Nimwegen E, Zavolan M, Rajewsky N, Schroeder M, Magnasco M, et al. Decay rates of human mRNAs: correlation with functional characteristics and sequence attributes. Genome Res. 2003 Aug;13(8):1863–1872.
2. Search of: mRNA vaccine | Completed Studies — List Results — ClinicalTrials.gov [Internet]. [cited 2021 Mar 1]. Available from: https://clinicaltrials.gov/ct2/results?term=mRNA+vaccine&Search=Apply&recrs=e&age_v=&gndr=&type=&rslt=
3. Pardi N, Hogan MJ, Porter FW, Weissman D. mRNA vaccines — a new era in vaccinology. Nat Rev Drug Discov. 2018 Jan 12;17(4):261–279.
4. How do we know the COVID vaccine won’t have long-term side-effects? [Internet]. [cited 2021 Mar 1]. Available from: https://theconversation.com/how-do-we-know-the-covid-vaccine-wont-have-long-term-side-effects-155714
5. Callaway E. The coronavirus is mutating — does it matter? Nature. 2020;585(7824):174–177.
6. Why some coronavirus variants are more contagious — and how we can stop them [Internet]. [cited 2021 Mar 1]. Available from: https://www.nationalgeographic.com/science/article/why-some-coronavirus-variants-are-more-contagious
7. A New Coronavirus Variant Is Spreading in New York, Researchers Report — The New York Times [Internet]. [cited 2021 Mar 1]. Available from: https://www.nytimes.com/2021/02/24/health/coronavirus-variant-nyc.html
8. New York City Coronavirus Variant B.1.526: What We Know [Internet]. [cited 2021 Mar 1]. Available from: https://nymag.com/intelligencer/2021/02/new-york-city-coronavirus-variant-b-1-526-what-we-know.html
9. Is the Covid-19 Vaccine Effective Against New South African Variant? — The New York Times [Internet]. [cited 2021 Mar 1]. Available from: https://www.nytimes.com/2021/01/25/health/coronavirus-moderna-vaccine-variant.html
10. Coronavirus: Is vaccine scepticism the next hurdle to overcome in the fight against COVID-19? | Euronews [Internet]. [cited 2021 Mar 1]. Available from: https://www.euronews.com/2020/11/23/coronavirus-is-vaccine-scepticism-the-next-hurdle-to-overcome-in-the-fight-against-covid-1
