KUALA LUMPUR – The Covid-19 pandemic may be nearing its end with the roll-out of various vaccines across the world.
Yesterday, Prime Minister Tan Sri Muhyiddin Yassin had announced that Putrajaya has entered into an agreement to purchase 6.4 million AstraZeneca vaccines.
But AstraZeneca is not the only vaccine the country will receive to fight the pandemic. Others include inoculations from Pfizer/BioNTech, Sinovac, CanSinoBIO, and Gamaleya.
While there is a small presence of anti-vaxxers in Malaysia who have expressed distrust for various forms of vaccines – not just the Covid-19 ones – a substantial number of Malaysians are worried about how fast these products are being rolled out.
Usually, vaccines take years of research and trials before acquiring approval to enter the market. So, are the Covid-19 vaccines safe?
Pfizer/BioNTech
Earlier this month, Pfizer announced its Pfizer/BioNTech vaccine’s preliminary results showed 90% effectiveness against the novel coronavirus.
The New York Times had reported that Pfizer's late clinical trial used placebos on half the recipients, with only 94 out of a total 44,000 recipients eventually contracting Covid-19.
Basically, the vaccine works through a synthetic ribonucleic acid (mRNA) messenger. When this synthetic mRNA enters a human body, it will replicate what is known as virus spikes, which trigger the body’s immune system to launch an attack, creating the necessary antibodies to fight the virus.
However, rumours had also surfaced that six people died after receiving the vaccine. However, a Reuters Fact Check article has suggested otherwise.
It said that four of the six deceased were not given the vaccine but the placebo.
One died of a heart attack; the second from a stroke, while the others died of unknown causes. A United States Food and Drug Administration (FDA) brief also suggested that there was no relation between the deaths and the placebo.
Meanwhile, one person who received a full double dose of the vaccine died of a heart attack 62 days later, and the other died from arteriosclerosis three days after receiving the first inoculation.
The FDA briefs similarly suggest that there is no relation between the vaccine and the deaths.
"All deaths represent events that occur in the general population of the age groups where they occurred at a similar rate,” the FDA briefing said.
Besides fatalities, another concern raised is the Bell’s Palsy side effect, in which a patient experiences weak or freezing muscles on one side of the face.
The FDA briefings confirmed there were four cases among patients who received the vaccine, but could not find a causal link between the immunisation and the side effect. Nevertheless, the FDA recommended that healthcare providers watch out for such side effects.
AstraZeneca
One of the oldest universities in the world, Oxford University, partnered with a Swedish company to develop a Covid-19 vaccine called AZD1222.
This vaccine, also reported to be 90% effective, works in a similar fashion to the Pfizer vaccine, but instead of using mRNA, the Oxford vaccine uses double-stranded DNA.
AstraZeneca basically places the gene of Covid-19 spikes into another flu-like virus called an adenovirus.
The New York Times had reported that this vaccine uses a more "rugged" approach than Pfizer's product.
While Pfizer's vaccine must be stored at -70°C, AstraZeneca's only needs to be refrigerated at 2°C to 8°C.
During the third phase of clinical trials, however, two participants experienced transverse myelitis, an inflammatory syndrome affecting the spinal cord.
However, AstraZeneca said that there was insufficient evidence to suggest a causal link between the vaccine and the symptoms.
Sinovac
China-based Sinovac Biotech is also developing a Covid-19 vaccine called CoronaVac. But its vaccine uses a much different method than Pfizer or AstraZeneca's.
CoronaVac is known as an inactivated vaccine, meaning it utilises parts of the virus grown in culture, which then loses disease-producing capacity.
Tests have revealed that the vaccine does result in quick immune responses from participants. However, the amount of antibodies produced in response to the vaccine was lower than the level found in patients who have recovered from Covid-19.
Meanwhile, Indonesia's Food and Drug Monitoring Agency (BPOM) confirmed that there are no critical side effects from the Sinovac vaccine.
CanSinoBIO
The Ad5-nCoV vaccine was developed by Chinese firm CanSino. It is similar to AstraZeneca's vaccine in that it contains the adenovirus engineered to carry Covid-19 genes.
Reuters recently reported that CanSinoBIO recruited about 20,000 participants for late-stage human trials and, in June, the vaccine was used on Chinese military personnel.
However, a media report revealed concerns over the use of the adenovirus, saying some immune systems may react to the adenovirus instead of the Covid-19 virus.
Gamaleya
The Gam-COVID-Vac is produced by Russia's state-run Gamaleya Centre. This vaccine also uses a similar approach to AstraZeneca, with one important difference.
Instead of using adenovirus vectors from chimpanzees, Gameleya uses human vectors. The purpose of these vectors is to carry the genetic materials of the Covid-19 spikes into the body.
In August, the Russian government approved the vaccine for use and claimed that it is 95% effective; however, some scientists raised concerns that early approval of the vaccine may have been the result of political intervention. – The Vibes, December 23, 2020
