2020 was challenging, but news of the COVID-19 vaccine arriving in Singapore last December allowed us to welcome the new year with a lot more hope. As the pharmaceutical companies scramble to ramp up production of more COVID-19 vaccines to help protect people against COVID-19 infection and its associated complications, news from the Health Sciences Authority (HSA) indicates that come the third quarter of 2021, there will be enough vaccines for everyone in Singapore to be inoculated.
At the moment, frontrunners in the coronavirus vaccine race include Moderna, Pfizer BioNTech, Sinovac Biotech and Oxford AstraZeneca. The vaccines protect against symptomatic forms of COVID-19, but it is still unclear whether they will stop the spread of the SARS-CoV-2 virus, the cause of COVID-19. Therefore, you should still continue to take appropriate precautions in protecting yourself and others around you even after receiving the COVID-19 vaccine.
Technology and the COVID-19 vaccine
Both the Moderna and Pfizer BioNTech’s vaccines use mRNA (messenger RNA) technology and it is interesting to note that there aren’t any mRNA vaccines for humans available on the market at this time.
mRNA vaccines work by injecting pieces of the virus’ genetic code into the body to provoke an immune system reaction which enables the body to defend itself against the coronavirus. The mRNA in the body breaks down fully within 48 hours. As it doesn’t enter the human nucleus, it does not affect human DNA. The 2 mRNA vaccines require 2 doses for adequate protection, and the doses are administered between 3 – 4 weeks apart.
Modified delivery virus
Oxford AstraZeneca and Sinovac Biotech’s vaccines employ a modified delivery virus (that usually causes symptoms such as the common cold) to introduce SARS-CoV-2 viral proteins to the immune system, which then mounts a defence against it. The delivery virus is attenuated or modified so you won’t develop the common cold when administered with this vaccine.
What are the differences?
Pfizer BioNTech’s vaccine has a reported 95% effectiveness while Moderna’s has charted a 94% efficacy. Conversely, Oxford AstraZeneca’s vaccine measured 70% efficacy overall, although there was a small group of volunteers that received a lower dose and recorded a higher 90% efficacy. Also, Sinovac Biotech has been found to be 50.4% effective – barely over the 50% needed for regulatory approval.
Additionally, the vaccines require storage at very low temperatures. The Pfizer BioNTech vaccine needs to be stored at around -70 Celsius while the Moderna vaccine can be stored at -20 Celsius. This means that transportation and distribution will pose challenges.
COVID-19 vaccines currently in use
Russia’s Sputnik V COVID-19 vaccine is cited to be more than 90% effective, but this is data from public vaccinations instead of from an ongoing trial. This vaccine has been rolled out for domestic use even though late-stage trials are not yet complete.
Moderna and Pfizer BioNTech vaccines
Moderna and Pfizer BioNTech have both received emergency use authorisation in many countries, such as the United States for the former, and here in Singapore and the United Kingdom for the latter.
As of 8 December 2020, the UK was the first country to start vaccinating its citizens with the Pfizer BioNTech vaccine. More than 100,000 people have been vaccinated in the first week alone with the programme set to scale up further. They have prioritised nursing home residents to be vaccinated first, especially the elderly who are over 80 years old and healthcare workers.
The Pfizer BioNTech vaccine has also been rolled out in the US with around 500,000 Americans vaccinated at the time of writing. The Moderna vaccine will also be administered to Americans. The vaccination of 21 million healthcare workers along with three million elderly Americans living in long-term care homes has started as well.
Myths & misconceptions
As with any medical innovation, there are a few misconceptions about the COVID-19 vaccines that have made its way through social media and messaging platforms.
Many people are under the impression that the production of these COVID-19 vaccines were rushed to be put on the market, and have not completed enough clinical trials.
Typically, vaccines take an average of about 10 years to develop and don’t usually get approved in less than 5 years. The key to the speed in which the coronavirus vaccines were developed is helped by the massive amounts of public funding that were committed to support the development and manufacturing of the vaccines. Conventional vaccines often use weaken or killed version of a virus. To do that, laboratories have to produce a huge amount of the virus that also include proteins which can spark a human immune response. Producing a virus and a viral-protein can be time-intensive and expensive. In the case of the Pfizer BioNTech and the Oxford AstraZeneca University vaccines, the process was faster because the mRNA technology used only required the use of a small part of the virus’s own genetic information to spark our immune responses to fight off the virus.
Researchers also already had prior knowledge when they first learned about SARS-CoV-2, the virus that causes COVID-19. Armed with experience and information about coronaviruses from the severe acute respiratory syndrome outbreak in 2003, researchers were able to quickly uncover and share the genetic sequence of the SARS-CoV-2 with the world early.
Advances in technology have also streamlined data-recording while social media made it easier to recruit people for human trials. As for approval, a ‘rolling review’ process – where information is released to healthcare regulators as soon as new data was acquired – helped speed up a process that would have traditionally taken between 6 – 9 months to achieve when data was submitted in batches.
It is said that the COVID-19 vaccine will prevent you from developing COVID-19 symptoms and allow you to test negative in a polymerase chain reaction (PCR) test. However, while it is true that none of the vaccines currently in use in Singapore contain live virus elements that could lead to the development of COVID-19, you may test positive on serology tests due to vaccine derived antibodies.
Also, there has been talk of the COVID-19 vaccine permanently and irreversibly altering our body’s genetic structure. That couldn’t be further from the truth. This is because an mRNA, or messenger RNA vaccine does not alter your DNA as the virus doesn’t actually enter the nucleus of the cells where our DNA lies. mRNA degrades quickly and is unable to persist or integrate into the human genome because the structure of our human genetic material is DNA, not RNA.
When will the COVID-19 vaccines be available?
On 21 December 2020, Singapore’s received its first shipment of the Pfizer BioNTech COVID-19 vaccine, with more to come in the coming months. We were one of the few countries to approve and obtain the vaccine. Vaccination will be on a voluntary basis with priority given to frontline and healthcare workers, followed by with the elderly and vulnerable. Vaccinations will be free for all Singaporeans and this includes long-term Singaporean residents currently residing here.
This nation-wide vaccination exercise will take time before everyone can get vaccinated and herd immunity built. It will be some time before life returns to normal.
Do note that pregnant women, people with allergies to drugs or food, compromised immune systems, and children under 16 years of age are not advised to receive the vaccine yet as there isn’t enough safety and efficacy data on them at the moment.
Even after receipt of the vaccine, we will still have to do our part by continuing to keep our hands clean with regular hand washing and sanitisation, mask wearing and social distancing.
Article reviewed by Dr Adrian Ong, infectious disease specialist at Mount Elizabeth Hospital.
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