3rd March 2021 – (Hong Kong) Having two vaccination options for the citizens is good but opening up the options to three or four is even better and it could make a major difference in getting the pandemic under control. CoronaVAC vaccine developed by China’s Sinovac has been found to be 50.4% effective in Brazilian clinical trials, according to the latest results released by researchers. It shows the vaccine is significantly less effective than previous data suggested – barely over the 50% needed for regulatory approval. To make matter worse, a 63-year-old elderly with a chronic illness was vaccinated with CoronaVAC vaccine by SINOVAC at the Community Vaccination Centre of Kwun Chung Sports Centre, Jordan last Friday and he passed away on 28th February.

Meanwhile, a Japanese woman in her 60s died from a brain haemorrhage three days after receiving a Pfizer coronavirus vaccination, the health ministry said on Tuesday, adding that there may not be a link between the two. The woman was vaccinated on Friday and is suspected to have suffered a brain haemorrhage three days later, on Monday, it said. It was Japan’s first reported death following a vaccination. Japan became the last member of the Group of Seven leading industrialised nations to begin its vaccination drive, on 17th February

Japan has so far received three shipments of vaccine developed by Pfizer and BioNTech. Cormitary vaccine available in Hong Kong is developed jointly by BioNTech and Fosun Pharma.

Meanwhile, concerns over the mRNA vaccine intensified following a Russia Today report during early February that all 78 residents at a nursing home in Madrid, Spain had tested positive for COVID-19 after being given their first dose of the Pfizer-BioNTech vaccine on 13th January, and at least seven people have died. A Chinese virologist advised elderly people, especially those with underlying conditions, not to take mRNA vaccine such as Pfizer’s, as it could induce their condition and worsen their health.

 South Korea’s Gyeonggi-do government announced on Wednesday (3rd) that it had received two reports in the past 24 hours that vaccinees had serious adverse reactions after being vaccinated with the COVID-19 vaccine developed by the British pharmaceutical company AstraZeneca and Oxford University, including slurred speech and decreased blood pressure. One of them died.

In January 2021, doctors in Norway have been told to conduct more thorough evaluations of very frail elderly patients in line to receive the Pfizer BioNTec vaccine against COVID-19, following the deaths of 23 patients shortly after receiving the vaccine.

According to Healthcareitnews, the key difference between the four main types of vaccines is the method of exposure used:


Vaccines include: Sinopharm, Sinovac

Number of doses required: 2 doses, intramuscular

Other licensed vaccines that use this type of technology: Hepatitis A, polio, rabies (all inactivated type) 

What to know: The whole virus vaccine uses a weakened or deactivated form of the pathogen that causes COVID-19 to trigger protective immunity to it. 

The two vaccines mentioned above – Sinopharm and Sinovac – both use inactivated pathogens, therefore they cannot infect cells and replicate, but can trigger an immune response.

Benefits: According to Gavi, the Vaccine Alliance (GAVI), the advantages of an inactivated whole virus vaccine include the fact its technology is well established, it is suitable for people with compromised immune systems, and it’s relatively simple to manufacture.

Challenges: Booster shots may be required.


Vaccines include: Pfizer-BioNTech, Moderna, Comirnaty

Number of doses required: 2 doses, intramuscular

Other licensed vaccines that use this type of technology: None

What to know: Since no other existing licensed or approved vaccine uses this type of technology, the Messenger RNA (mRNA) variety could be mistaken for something completely new to healthcare. However, a number of mRNA vaccines have been studied in the past for illnesses and diseases including cytomegalovirus (CMV), influenza, rabies, and the Zika virus.

According to the Centers for Disease Control and Prevention (CDC): “Researchers have been studying and working with mRNA vaccines for decades. Interest has grown in these vaccines because they can be developed in a laboratory using readily available materials. This means the process can be standardised and scaled up, making vaccine development faster than traditional methods of making vaccines.”

So how does it reportedly work? The COVID-19 RNA vaccine consists of mRNA molecules made in a lab that code for parts of the SARS-CoV-2 virus – specifically the virus’ spike protein.

Once injected into the body, the mRNA instructs the cells to produce antigens – such as the spike protein mentioned – which are then detected by immune cells, triggering a response by the body’s lymphocytes.

The killer T-cells destroy the infected cells, while the B-cells and helper T-cells support antibody production. Whoever is exposed to the COVID-19 coronavirus in the future would have an immune system that recognises it, and in turn fight off the infection.

Benefits: According to the University of Cambridge’s PHG Foundation, advantages include good safety (since there are no live components, there’s no risk of the vaccine triggering disease), reliability, and that it’s relatively simple to manufacture.

Challenges: Disadvantages include unintended effects (such as an unintended immune reaction), ensuring effective delivery into the body (since free RNA in the body is quickly broken down), storage issues, plus the fact that this type of vaccine has never previously been licensed for humans.


Vaccines include: Oxford-AstraZeneca, Sputnik V (Gamaleya Research Institute)

Number of doses required: 2 doses, intramuscular

Other licensed vaccines that use this type of technology: Ebola

What to know: This type of vaccine introduces a safe, modified version of the virus – known as “the vector” – to deliver genetic code for the antigen. In a COVID-19 vaccine, the “vector” is the spike proteins found on the surface of the coronavirus.

Once the body’s cells are “infected”, the cells are instructed to produce a large amount of antigens, which in turn trigger an immune response.

Benefits: Viral vector-based vaccination is another well-established technology that can trigger a strong immune response as it also involves both B cells and T cells.

Challenges: Previous exposure to the vector could reduce effectiveness, plus these types of vaccines are relatively complex to manufacture compared to others.


Vaccines include: Novavax

Number of doses required: 2 doses, intramuscular

Other licensed vaccines that use this type of technology: Hepatitis B, meningococcal disease, pneumococcal disease, shingles

What to know: The protein subunit vaccine contains purified “pieces” of a pathogen rather than the whole pathogen to trigger an immune response. It is thought that by restricting the immune system to the whole pathogen, the risk of side effects is minimised.

Benefits: The protein subunit vaccination is also a well-established technology that’s advantageous for those with compromised immune systems.

Challenges: This type of vaccine is relatively complex to manufacture, and adjuvants and booster shots may be required.

Source: Statista

At present, vaccination programs have been launched in many places around the world, but the vaccines have side effects and certain risks. For example, there is a chance of muscle cramps and hyposmia after vaccination with SINOVAC vaccine. Comirnaty vaccine may cause temporary facial sagging. According to the vaccine information provided by the Department of Health, people who have had severe allergic reactions to the vaccine in the past (such as acute allergic reactions, angioedema, dyspnea, etc.), people with severe neurological diseases, patients with uncontrolled severe chronic diseases, and pregnant women r women who are breastfeeding should not be vaccinated. As for those suffering from acute diseases, acute episodes of chronic diseases, severe chronic diseases, allergies, and fever, it should be used with caution. If necessary, the vaccination should be delayed after being evaluated by a doctor.

Diabetic patients and those with convulsions, epilepsy, encephalopathy, or a history of mental illness and family history should also be cautious. In addition, whether the elderly and children are vaccinated should also be carefully evaluated. As the clinical data of SINOVAC vaccine admits that there is insufficient evidence for the protection rate of the elderly over 60 years old, the Department of Health still stated that “the benefit of vaccination is higher than the risk.”

Regarding the Comirnaty vaccine, the Department of Health does not recommend vaccination for children under the age of 16 and women who are pregnant or breastfeeding. If citizens have experienced severe allergic reactions or breathing problems after any vaccination in the past, fainted after any injection, suffered from a serious illness or infection accompanied by a high fever, the vaccination should also be delayed.

The Hong Kong government has also ordered the AstraZeneca vaccine in collaboration with the University of Oxford (ChAdOx1 nCoV-19) vaccine using a non-replicating viral vector as a third option.

Having said that, the stigma attributed to these unfamiliar brands of vaccines and isolated incidents of deaths and adverse reactions may outweigh the benefits even though most governments are rushing to contain the pandemic by pushing citizens to vaccinate themselves with whatever vaccines they can get their hands on regardless of the brands. Many citizens may be reluctant to vaccinate themselves despite the government’s efforts to explain that the benefits outweigh the risks. This is purely due to psychological fear created by the isolated deaths and also most adults rarely visit clinics for any form of vaccination nowadays against any epidemic. The whole new experience of injecting some foreign liquid into their bodies without knowing the short or long term side effects on them will result in many taking a back step, hence, hindering the government’s efforts to achieve herd immunity in the shortest span of time and reopen the economy as soon as possible.

The possible solution to change their minds is perhaps offering them more choices. A fifth option has recently emerged i.e. J&J vaccine which is described as a ‘game changer’ by Dr. Muriel Jean-Jacques, an assistant professor of medicine at Northwestern University. Millions of doses of the COVID-19 vaccine developed by Johnson & Johnson will soon be available in the U.S., a much-anticipated development that could help turn the tide of the pandemic by vastly speeding the rate at which people are vaccinated.

According to Denise Chow of NBC News, experts say the newly authorised vaccine could play a key role in staving off another surge of infections, particularly as the recent sharp declines in reported cases of COVID-19 appear to be levelling off and rising once again. “We’ve never had to vaccinate our whole population at the same time before — not to mention the rest of the world — so having more vaccines will make that easier,” Jean-Jacques said. The single-dose vaccine, manufactured by a Johnson & Johnson subsidiary called Janssen Biotech, received emergency use authorisation from the FDA on Saturday. The company shipped out 4 million doses Monday, with 16 million more doses expected by the end of the month.

The vaccine’s authorization is a significant milestone, because it will help ease the supply and distribution bottlenecks that have hampered the rollout of vaccines across the country, said Dr. Stella Safo, an HIV primary care physician who is an assistant professor of medicine at the Icahn School of Medicine at Mount Sinai.

The Johnson & Johnson vaccine does not require ultra-cold storage conditions, as the vaccines made by Moderna and Pfizer-BioNTech do, and it can instead be kept in regular refrigerators. That could ease some distribution challenges, particularly in rural communities.

J&J vaccine requires only a single dose, unlike Pfizer, SINOVAC or Comirnaty vaccines which require two shots three to four weeks apart. A single-dose vaccine could help boost the country’s rate of vaccination, and increasing the number of people vaccinated each week will be critical for containing new outbreaks, especially as more contagious variants of the coronavirus become more widespread. Importantly, the data released shows the vaccine works against all variants. The vaccine was less effective at preventing symptomatic illness in South Africa, where the variant first detected there is dominant, but it was still highly effective at preventing severe disease there. J&J also released preliminary data indicating the vaccine likely helps prevent asymptomatic infections, and that the Brazil variant doesn’t appear to have as much of an impact on vaccine efficacy as the South African variant.

An analysis by the Food and Drug Administration found that the Johnson & Johnson vaccine was 85 percent effective at preventing severe COVID-19 and 100 percent effective at preventing death. In the U.S., the single dose was 72 percent effective at preventing moderate to severe disease.

Moderna’s vaccine is 94 percent effective at preventing symptomatic COVID-19, and Pfizer’s vaccine was found to be 95 percent effective. But experts said the three vaccines should not be compared based on those numbers alone, because they all provide strong protection against severe disease.

“All three of them are really quite good, and people should take the one that’s most available to them,” Dr. Anthony Fauci, director of the National Center for Allergy and Infectious Diseases, said Sunday on NBC’s “Meet the Press.”

The Johnson & Johnson clinical trials also took place later in the pandemic and in regions where worrisome variants of the coronavirus have emerged.

The Johnson & Johnson vaccine is the third to receive emergency authorisation from the U.S. Food and Drug Administration following Moderna and Pfizer-BioNTech. While the Pfizer and Moderna vaccines performed somewhat better in clinical trials, all three vaccines are considered safe and effective. In summary, the key advantages of Johnson & Johnson vaccine are it requires only one shot, and studies show it may curb spread of the virus. The other vaccines use a new technology called mRNA, which allowed for faster design and testing of vaccine but resulted in a product that required more stringent storage conditions. Johnson & Johnson’s vaccine, which uses viruses to deliver genes into cells, can keep for three months at normal refrigeration temperatures, making it easier to distribute and easier for pharmacies and clinics to stock. At US$10 a dose, it is also cheaper than the other two.