Mersad Alimoradi 27 Dec 2020

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Updated 1st August 2021

This article is continuously updated.

A global mass vaccination is currently underway in an effort to end the COVID-19 pandemic. Several candidate vaccines have been approved by international health authorities, and most countries are using multiple vaccine types to speed up the process.

The most famous COVID-19 vaccines that have already been approved or are about to be approved are Pfizer/BioNTech, Moderna, Oxford/AstraZeneca, Russia's Sputnik V vaccine, China's CoronaVac and Sinopharm vaccines, and several others. There’s a lot of news going on around these different vaccines, so how do they compare?


The Pfizer/BioNTech vaccine was the first COVID-19 vaccine to reach the final stages of testing. It is currently the most widely approved COVID-19 vaccine on the market and is distributed and administered worldwide. The Pfizer vaccine was developed through a wonderful collaboration between Pfizer, the American pharmaceutical giant, and BioNTech, the German biotechnology company.

Vaccine Specifics: The Pfizer/BioNTech vaccine is an mRNA vaccine and not a traditional vaccine. While mRNA vaccines have never been previously used in humans outside of trial settings, the Pfizer/BioNTech vaccine has been approved by various health authorities around the world, such as the United States Food and Drug Administration (FDA) and the World Health Organization (WHO). You can check our article on mRNA vaccines to learn more about how they work.

Effectiveness: Pfizer has reported that the vaccine is 95% effective in preventing corona infections and that the vaccine is safe and causes no serious side effects. The data is based on a clinical study that involved more than 43,000 individuals. Newer studies done after approval showed similar effectivity. 

Logistics: The Pfizer/BioNTech COVID-19 vaccine is administered in 2 doses, with each dose estimated to cost $19.50, 3 weeks apart. However, the vaccine poses a logistical problem, as it can only be stored at -70°C, which can be problematic, especially in underdeveloped countries where such refrigeration is not widely available. Nevertheless, national and international distribution plans are being implemented to meet these logistic needs. Pfizer has promised to produce up to 1.3 billion doses by the end of 2021.

Approval for teenagers and children: In May, The European Union’s Medical Agency (EMA) and the FDA have granted approval for the Pfizer vaccine to be used in adolescents aged 12-15 in an effort to further slow down the spread of COVID-19. Teenager COVID-19 vaccination has already started in the US and should be underway in Europe as well as soon as the first week of June. 

Many parents remain reluctant to give their children the jab, however, all major health authorities are recommending it as a safe and protective intervention. A recent study of 2,260 young adolescents showed that the vaccine was 100% effective against symptomatic infection in children aged 12 to 15. 

1-June-21 Update: 

  • The Pfizer vaccine seems to be protective against the Indian and UK variants, according to a newly released study.  

30-June-2021 Update: 

  • A new study published in Nature suggests that the Pfizer/Biontech vaccine can provide long-lasting immunity. The vaccine not only stimulates “memory” immune cells, but it also leads to the formation of long-lived “Germinal Centers” in your lymph nodes. These centers can produce antibodies for months or years and have the potential to be more effective against new variants. 
  • According to recent studies from Public Health England, the Pfizer vaccine seems to be highly effective against the new corona Delta (1.617.2) variant. The vaccine provides 96% protection against hospitalization in patients infected with this new highly infective strain. 

1-August-2021 Update: 

  • A large recent analysis involving 44,000 people showed that the Pfizer/BioNTech vaccine maintains an effectiveness of more than 86% after 6 months of vaccination. The vaccine was also found to be highly effective against the South African corona variant. 
  • Pfizer and BioNTech have announced that they will be holding clinical trials to see if a booster shot will be necessary with the growing concerns around the delta variant. So far, the CDC and FDA do not recommend a third dose.
  • A new study showed that the Pfizer vaccine is 88% effective against the delta variant in fully vaccinated people. 
  • Pfizer has announced that it will be testing the BioNTech vaccine in children aged 5-11, with the results to be expected next September. 
  • Pfizer has announced plans to seek approval for a third “booster” shot in light of the new delta variant. The FDA and CDC, though, still do not recommend a third shot. 

Moderna vaccine

Moderna is an American biotechnology company that made headlines in 2020 after announcing its mRNA COVID vaccine. The vaccine uses the same technology as that used by Pfizer/BioNTech and has also been well received by health authorities around the world. Currently, Moderna is most actively distributing in the United States, however, millions of doses have already reached the EU and other countries as well. 

Effectiveness: Compared to Pfizer, Moderna’s vaccine is also 95% effective in preventing infection with the novel coronavirus. 30,000 people participated in Moderna’s phase III clinical trial, and researchers concluded that the vaccine is safe, and causes only rare side effects. Many countries have also authorized the vaccine for pregnant and breastfeeding women. 

Logistics: Moderna’s vaccine is given in 2 spaced doses, like most other available COVID-19 vaccines. The costs are estimated to range between $32 and $37. As for logistics, Moderna’s mRNA vaccine must be stored at -20°C, which is also a challenge in third-world countries. 

1-June-21 Update: 

  • Moderna is now seeking to get the FDA’s approval for use in children aged 12 to 18. The company has released very promising results from a study involving 3,732 children in this age group. The study results, announced on May 25th, showed that the
  • Moderna vaccine is very safe in children above 12 years, and provides 100% protection against COVID-19. 

30-June-21 Update: 

  • Moderna has filed to Health Canada and the European Union’s Medical Agency (EMA) to get approval in adolescents (aged 12 to 17). The authorization is still pending, as it is with the FDA.

1-August-21 Update: 

Oxford/AstraZeneca vaccine

The collaboration between Oxford University and the British-Swedish pharmaceutical company AstraZeneca yielded a COVID-19 vaccine that has also been widely endorsed. The Oxford vaccine is a traditional vaccine, not an mRNA vaccine like those from Moderna and Pfizer/BioNTech. The vaccine introduces the COVID-19 “spike protein” to the body using a common cold virus that’s been modified to be completely harmless.

Effectiveness: To test the vaccine’s efficacy, the research group analyzed results from over 11,000 volunteers. The researchers concluded that the Oxford/AstraZeneca vaccine is 90% effective in preventing coronavirus infections. Among those who received the vaccine and still got infected, the study group found that all cases were mild and none were severe. This means that even if you’re one of the unlucky 10% who don’t get the full benefit of the vaccine, you’d still be protected from severe infection. Safety data derived from over 20,000 participants revealed that the vaccine is well tolerated and safe in the general population.

Logistics: The Oxford/AstraZeneca vaccine is also given in 2 doses, each of which costs between $3 and $4. Recent research suggests that a 12-weeks gap between doses is more effective. Compared to the mRNA vaccine, the Oxford/AstraZeneca vaccine is easier to store and requires only standard refrigeration at 2-8°C. 

Blood clot concerns: The WHO issued a reassuring statement and recommended all countries continue vaccination with AstraZeneca, noting that the benefits far outweigh the risks. The European Medicines Agency’s (EMA) safety assessment committee concluded on April 7, 2021, that unusual blood clots should be listed as a very rare side effect of AstraZeneca’s vaccine, suggesting a potential causal link, putting Oxford-AstraZeneca's COVID vaccine back on track.

Age limits for AstraZeneca’s vaccine: Italy has recommended that AstraZeneca's COVID-19 vaccine should only be used for people over the age of 60. Plus, the Italian health authority declared that people under 60 years of age who have received a first shot of AstraZeneca’s vaccine can also receive a second one. The United Kingdom, meanwhile, has recommended an alternative to AstraZeneca's vaccine for people younger than 30 because of evidence of its link to rare blood clots. Many other countries as well are now following an age limit for AstraZeneca. 

1-June-21 Update:

  • According to a new study from Public Health England, the AstraZeneca vaccine is 60% protective against the Indian variant, and 66% protective against the original UK variant. However, the authors reported that 2 full doses need to be given to be effective. 

30-June-21 Update: 

  • According to recent studies from Public Health England, the AstraZeneca vaccine provides protection against hospitalization from the Delta variant infection. The study found that the vaccine protects 92% of those infected. 
  • A new study is underway to test an AstraZeneca booster shot against the South African COVID-19 variant. It is planned to involve around 2,250 volunteers. 
  • An Oxford University research team announced that a delay for up to 10 months between the two doses can produce a much more robust immune response. 
  • In addition, they found out that a third booster shot given after 6 months of the second dose can greatly strengthen protection against COVID. 
  • The same research group announced that there is still no evidence that a third shot is actually needed. 

1-August-21 Update: 

  • AstraZeneca will be testing its vaccine efficacy in 300 young children aged 6 to 17 years.


So far, three "imported variants" - British, South African, and Brazilian - have been detected in India. Serum Institute of India's COVID-19 vaccine, called Covishield, is a version of the Oxford-AstraZeneca vaccine that Indian manufacturers produce locally. This vaccine is effective against the UK and Indian variants but is awaiting efficacy data against the Brazilian strain.

Effectiveness: The two-dose Covishield regimen showed 62% efficacy in Phase 3 clinical trials.

Logistics: The vaccine requires two doses to build immunity, administered 28 days apart. In addition, it does not require sub-zero storage and is stable at 2-8°C. In private facilities, the government has set a ceiling price of 250 rupees, equal to 3.33 U.S. dollars, for both vaccines (Covishield and Covaxin). Covishield accounts for 90% of the doses administered in India so far, with the rest being Bharat Biotech's Covaxin. 

Blood clot concerns: After European and British regulators raised a possible link between AstraZeneca's vaccine and a few rare cases of blood clots, the Indian panel is investigating the safety of this vaccine. However, no cases of blood clotting disorders have been reported in India. 
30-June-21 Update:

  • Since COVISHIELD is another brand of the same Astrazeneca vaccine, it’s expected that it is also effective against the Delta variant. Moreover, experts also suggest that 10-months spaced doses or a booster 3rd dose might provide much more protection. 
  • India is considering adopting a 12-week gap policy between each dose. This has proven to provide more protection and allows to vaccinate more people faster. The first dose alone provides significant protection in between jabs (76%).


India's Bharat Biotech has partnered with the National Institute of Virology and the Indian Council of Medical Research to produce an inactivated coronavirus vaccine called Covaxin. India approved the vaccine for emergency use on January 3, based on promising early trial results. 

Vaccine Specifics: Covaxin works by teaching your immune system to produce antibodies against the SARS-CoV-2 coronavirus. The antibodies bind to viral surface proteins, such as the "spike" protein. Covaxin was found to be effective against both the UK and Brazilian variants.

Effectiveness: Phase III trial results showed 77.8% efficacy on a trial that involved 25,800 participants. The results were released in June 2021. 

Logistics: Covaxin is similar to Covishield in terms of the dosing regimen. In addition, it can be stored at 2-8 degrees Celsius. Bharat biotech has been approached by several countries around the world to supply COVAXIN®. These include Mongolia, Myanmar, Sri Lanka, Philippines, Bahrain, Oman, Maldives, and Mauritius.

1-June-21 Update: 

  • India plans to boost Covaxin production in 2021, with an estimated 550 million doses to be produced between August and December of this year. Brazil has recently ordered 20 million doses of Covaxin, which is currently approved in the country. 

30-June-21 Update: 

  • After a long wait, the Covaxin phase III trial results were released. The vaccine seems to be 77.8% effective against the coronavirus. 

1-August-21 Update: 

Russian Sputnik V vaccine

The Gamaleya National Center in Russia announced positive results with its COVID-19 vaccine in November 2020.

Vaccine Specifics: The vaccine is designed using traditional methods. It is very similar to the Oxford/AstraZeneca vaccine, where a modified harmless adenovirus vector is used to deliver the COVID-19 spike protein to the body to develop immunity against it. 

Effectiveness: The Gamaleya National Center announced that the vaccine is 92% effective in protecting against COVID-19, based on a clinical trial that enrolled 20,000 volunteers. Researchers reported that the vaccine is safe, with very minimal side effects. The results were published last February in the famous medical journal, The Lancet, and have received worldwide recognition. A recent study done on 81,000 individuals in the UAE showed that the Sputnik V had 97.8% effectiveness

Logistics: Sputnik V is estimated to cost about $10 per dose, and two doses are needed as with the other vaccines, 21 days apart. Same as with the Oxford vaccine, Sputnik V is fairly easy to store and requires only standard refrigeration.
Mass vaccination with the Sputnik V is currently underway in Russia and many other countries like Brazil, Argentina, Iran, and China. The Gamaleya National Center is also collaborating with those countries to allow them to produce the vaccines locally to speed up the rate of vaccination. Indian regulatory authorities have also approved the Russian Sputnik V COVID-19 vaccine.

Sputnik Light Vaccine: A new one-dose version of the Sputnik V has been approved earlier in May 2021 by the Russian government. Researchers announced that the single-dose COVID-19 vaccine is 79.4% effective in protecting against corona. 

1-June-21 Update: 

  • There have not been any concerning reports with the Sputnik V vaccine as there have been with other vaccines, and so far it seems to be very well-tolerated and protective against the coronavirus. However, the WHO and EMA have still not approved it for unclear reasons. Nevertheless, many countries have already approved the vaccines and millions of doses have been administered successfully. 
  • India has announced that Sputnik V will start rolling out after the second week of June. This makes Sputnik V the third approved COVID-19 vaccine in India, after COVISHIELD and COVAXIN. Russia will be sending 125 million doses of Sputnik V to India by August. 
  • The Russian government has signed a deal with India to start producing Sputnik V there as of August 2021. The deal involved the production of 750 million doses in 6 domestic Indian centers, which will significantly boost the rate of vaccination in the country and worldwide. 

30-June-21 Update:

  • South Korea will start producing the Sputnik V and single-dose Sputnik Light vaccines locally starting summer or early fall. 
  • Russia is working to get approval in the EU, however, it is still not clear when the authorization should be expected. 
  • A recent study done on 81,000 individuals in the UAE showed that the Sputnik V had 97.8% effectiveness

1-August-21 Update:


The CoronaVac COVID-19 vaccine was developed by the Chinese biopharmaceutical company Sinovac. 

Vaccine Specifics: The vaccine was also produced using a traditional method, but it is somewhat different from the Sputnik V and Oxford/AstraZeneca vaccines. CoronaVac uses inactivated viral particles that are injected to build immunity against COVID-19. 

Effectiveness: Data from phase III trials, conducted in Turkey, Chile, Indonesia, Philippines, and Brazil, reported highly variable outcomes. Nevertheless, the vaccine seems to completely prevent severe disease in all trials. A large analysis released in May reported 65% protection against symptomatic COVID-19 infections with 86% protection against death. 

Logistics: CoronaVac’s cost is still unclear with different sources citing different costs ranging from $13.6 to $60 per dose. Two doses of the vaccine are required to establish immunity, just like the other four vaccines discussed earlier. CoronaVac requires no complex logistics for storage and transfer, and standard refrigeration is sufficient.

Countries like Brazil, Mexico, Turkey, and Ukraine, and others have already authorized and ordered the vaccine. 

1-June-21 Update: 

  • Coronavac (Sinovac) has received emergency use approval from the WHO on June 1st, 2021. It has become the second globally approved Chinese vaccine after Sinopharm. 
  • The Chinese government has already provided the first batch of the vaccine to COVAX to be globally distributed. The Egyptian government is already planning to produce the vaccine locally, with 2 million doses as a start. 
  • It needs to be noted that despite the delay in the WHO’s approval, more than 70 million doses of Coronavac have already been administered in China and other countries as well. 
  • Sinovac believes that the vaccine can also be administered in children as young as 3 years of age, and it has been approved by the government for this age group. Complete data is still lacking about vaccination in children, but a large clinical trial is already underway. 
  • According to the latest study results (released last May), Coronavac appears to be 65% protective against COVID-19 infections and can prevent death in 86% of cases

30-June-21 Update: 

  • A new study published in The Lancet announced that the CoronaVac was safe and effective in children aged 3 to 17. The study involved 550 participants in this age group and reported no serious side effects. The vaccine is already approved by the Chinese government for this age group. 
  • Indonesia announced the authorization of Sinovac in children aged 12 to 17. 

1-August-21 Update: 

  • Sinovac has announced that their vaccine is effective against the delta variant, however, there’s still no concrete data to support this claim. 

Sinopharm vaccine

The Chinese state-owned pharmaceutical company Sinopharm has also announced optimistic results with its COVID-19 vaccine. 

Vaccine Specifics: The Sinopharm vaccine is very similar to CoronaVac, the other Chinese vaccine, and both are based on an inactivated version of the COVID-19 virus. The vaccine was approved by regulators in the United Arab Emirates and Bahrain after Sinopharm announced that the vaccine is safe and effective in preventing COVID-19 infections. 

Effectiveness: The company declared that its vaccine is 79% effective, based on a trial that involved around 31,000 volunteers. Over 100 countries have already placed orders on the new Chinese vaccine.

Logistics: The Sinopharm vaccine is also administered in 2 doses, with the cost of each dose estimated at about $75. Only standard refrigeration is needed to store the Sinopharm vaccine, making it a good candidate for developing countries.

1-June-21 Update: 

  • Earlier in May, the WHO granted emergency use authorization for Sinopharm, making it the first non-western vaccine to receive approval. The responsible committee announced that the efficacy and safety results from Sinopharm are encouraging, and its approval would help speed up corona vaccination around the world. 
  • On May 25th, a large study was published in The Journal of the American Medical Association (JAMA), confirming the efficacy of the Chinese vaccine. The study involved 40,000 volunteers in vaccination centers in Egypt, UAE, Bahrain, and Jordan. Researchers found that the Sinopharm COVID-19 vaccine is 72.8% to 78.1% effective against corona, which is in line with the WHO’s decision. 

30-June-21 Update:

  • According to the latest reports, it is still unclear whether the Sinopharm vaccine is effective against the newly spreading Delta variant
  • A new trial in the UAE will assess Sinopharm’s vaccine safety and efficacy in children aged 3 to 17. The study will involve 900 children who will receive the jab. 
  • The UAE have started giving out an additional Pfizer booster dose to those who had already taken 2 doses of Sinopharm. The dose is given 6 months after the last Sinopharm jab.  

1-August-21 Update:

  • A new study done in Sri Lanka found that the Sinopharm vaccine induces a similar immune response against the delta variant compared to natural infection. 
  • After conducting extensive research and trials, The UAE's Ministry of Health and Prevention (MOHAP) announced that Sinopharm Covid-19 vaccine can now be administered to children and adolescents, between age of 13-17 years.

Johnson & Johnson 

Johnson & Johnson is another American medical device and pharmaceutical company that recently entered the market with its new vaccine. Johnson & Johnson’s single-dose COVID-19 vaccine is the third vaccine to receive emergency use approval from the FDA in February, following Pfizer and Moderna. One of the main advantages of J&J's vaccine is that it is administered in a single dose
Vaccine Specifics: It is an adenovirus vaccine that works similarly to AstraZeneca and Sputnik V. 

Effectiveness: The efficacy in preventing COVID infections is slightly less than other licensed vaccines. Johnson & Johnson reported that their vaccine was 66% effective in preventing moderate to severe COVID infections, and 100% effective in preventing hospitalizations and deaths. These figures reflect the vaccine’s efficacy against symptoms, not an actual infection. Nevertheless, the FDA announced that transmission risk from asymptomatic patients is negligible, and therefore symptomatic prevention is beneficial. 

Logistics: The one-shot vaccine is now being administered in the US, EU, and many other countries as well. Germany is planning to make J&J available to all adults, regardless of their age or risk group to speed up vaccination. 

Blood clot concerns: First it was AstraZeneca. Now it's Johnson & Johnson. In April 2021, several cases of blood clotting in the United States were reported after receiving the J&J vaccine. After reviewing the available data, the WHO announced that Johnson & Johnson’s COVID-19 vaccine is safe, and that blood clotting is a very rare adverse event. The WHO recommended continuing the use of the J&J vaccine since the benefits greatly outweigh the negligible risks. The FDA also issued a similar statement before resuming vaccination with Johnson & Johnson. 

30-June-21 Update:

  • According to preliminary news, the J&J vaccine might be only 60% protective against the new delta Indian variant. However, further investigations are still necessary before making any assumptions. 
1-August-21 Update:


Novavax is a US-based company specializing in the development of innovative vaccine technologies to treat serious infectious diseases. The Novavax COVID-19 vaccine has shown great promise and may be one of the best vaccines developed to date. 

Vaccine Specifics: This vaccine uses a technology different from those previously listed. Novavax is a subunit vaccine, which means that it’s made of proteins that mimic the COVID’s spike protein and subsequently initiate an immune response. The main advantage of Novavax over other innovative vaccines (such as Pfizer and Moderna) is that it’s easier and quicker to manufacture, and requires regular refrigeration for storage. 

Effectiveness: Results from Novavax's Phase III trial, conducted in the UK and South Africa, were very promising and tested the vaccine’s efficacy against the UK and South African COVID variants. The efficacy of Novavax against the original COVID-19 variant is 90.4%, which is comparable to other vaccines. The company announced 100% protection against severe disease. Moreover, the vaccine was 93.2% effective against variants of interest and concern. The study included 29,960 participants and the results were announced in June 2021. 

Although Novavax entered the scene a bit late, it’s one of the first vaccines to be thoroughly tested against newly emerging COVID variants. Novavax is still not approved for public use, however, the company is expecting to receive emergency use authorization in the US and UK in May. Novavax is given in two spaced doses, just like the other variants mentioned earlier.  

1-June-21 Update: 

  • Novavax has announced some disappointing delays in the planned rollout of their vaccine. The company is promising to apply for approval during the second half of 2021. By then, Novavax hopes to be better prepared for production and will have more results from their ongoing clinical trial. 

30-June-21 Update: 

  • Phase III trial results were announced showing high rates of efficacy reaching 90.4%. In addition, researchers found out that the vaccine was highly effective against new corona variants (93.2%)


A new Chinese vaccine has recently been approved for public use in China. This vaccine is, like J&J’s, a single-dose vaccine, and it’s an adenovirus-based viral vector vaccine, similar to Sputnik V. CanSinoBIO’s vaccine has shown 66% efficacy in preventing COVID symptoms and 91% in preventing severe disease. No serious blood clot cases had been reported in people inoculated with its single-dose COVID-19 vaccine. CanSinoBIO’s vaccine is approved in China, Hungary, Chile, and Pakistan. 


The fifth and latest Chinese vaccine to be approved is the one developed by Anhui Zhifei Longcom Biopharmaceutical Co. Ltd. and the Chinese Academy of Sciences. It is a sub-unit vaccine, similar to Novavax. Phase III trials are currently underway in several countries around the globe. The manufacturer says that the vaccine is safe and effective against COVID-19, however, there is no public data to confirm this yet. 

Although the Anhui Zhifei Longcom vaccine offers the convenience of regular refrigeration storage, it has a major downside: a three-dose regimen. Receivers will have to take 3 shots with a month between doses.

Mixing and matching COVID-19 vaccines

Can you take different types of COVID vaccines? Can you mix them? Many studies are currently underway to determine if we can use different types of vaccines for the first and second doses. 

Recent data released by Oxford researchers suggest that mixing AstraZeneca with Pfizer/BioNtech produces a “robust immune response”. The response was observed to be stronger when the AstraZeneca jab was given as the first dose, followed by

Pfizer compared to when Pfizer is given as the first shot. 

The German Chancellor, Angela Merkel, had received the first shot of AstraZeneca, followed by a second shot of Moderna to encourage mixing and matching efforts. 

A combination of Sputnik V and AstraZeneca is currently being tested in several countries like Azerbaijan, the United Arab Emirates, and Belarus. Results are expected to follow in the next few months. 

In the UAE, health authorities are already offering an extra Pfizer shot to those who already got 2 doses of the Sinopharm vaccine. 

The combination of vaccines could provide broader and longer-lasting immunity against the virus and its new variants. It may also offer greater flexibility in vaccine deployment.

Is a booster shot necessary? When will the booster shot be given?

Regulatory authorities and vaccine developers are now questioning the need for booster doses. A recent announcement by an Oxford University study group announced that a third shot might not be necessary. 

However, the fear that new variants of the new coronavirus could weaken the protection of vaccines designed against older strains remains. For this reason, some manufacturers are testing a third booster shot as a viable option. 

Sinovac is already leading a clinical trial in China, with participants receiving a third dose about eight months after receiving the second. Pfizer has announced that a third dose might be required in 6 - 12 months, followed by a yearly vaccine. AstraZeneca booster shots have already proved effective in boosting immunity when given after 6 months of the second jab. Sinopharm and Pfizer booster shots are already available to all previously fully vaccinated citizens in UAE after 6 months of their second dose. 

The answer to whether a booster shot is necessary or not should be based on the results of future phase III clinical trials. Preliminary results to date indicate that booster vaccination can successfully increase neutralizing antibody titer and antibody persistence. It can also effectively improve the vaccine's ability to resist mutation.

How effective are the vaccines against new delta variants? 

The Delta (1.617.2) variant was first detected in India in December 2020. Since then it has spread very fast to become the most dominant variant in the UK and India. Experts expect that the delta variant will be dominant globally, after reports of outbreaks from all around the world. 

The problem is that the delta variant is extremely contagious and spreads much faster than the original coronavirus strain. Authorities also fear that available vaccines and treatments might not be as effective against the new variant. 

So far, the vaccines that seem to be effective against the new delta variant include: 

  • Pfizer/BioNtech
  • Oxford/AstraZeneca and Covishield
  • Novavax 
  • Johnson & Johnson 

The results are still early in most cases and more testing is needed to confirm them. 

Should I Do An Antibody Test After My Vaccine?

Currently, health authorities do not recommend getting an antibody test after being vaccinated. Many people believe that by doing this, they can confirm whether they are immune or not, however, this isn’t true.

Although it is likely for a positive antibody test to imply immunity, and a negative test to imply the lack of it, there is still no clear data to support this, according to the CDC

Moreover, some antibody tests do not detect specific immunogenic antibodies, and as such, their results cannot be used to assume the presence or absence of immunity. There is still also no clear relationship to suggest that higher titers of antibodies mean higher immunity.

However, some people still might want to get an antibody test and therefore they are offered at various hospitals worldwide. It is best to talk to your doctor with help understanding the results.

To Be Or Not To Be Vaccinated

Every single health authority around the world recommends that you get vaccinated to protect yourself, break the chain of infectivity, and prevent new mutants from developing.

As extensively reported and explained in this article, three things we know for sure:

  1. The approved COVID-19 vaccines are safe
  2. The approved COVID-19 vaccines are effective
  3. The approved COVID-19 vaccines are necessary

This is especially true with the spread of the delta variant which spreads 50% more rapidly compared to other variants. To put things into perspective and highlight how important it is to get vaccinated, here’s how vaccinated and unvaccinated people compare in terms of hospitalization and death:

  • French health authorities reported that up to 96% of new cases in France are unvaccinated after a new delta variant outbreak.
  • A recent analysis showed that up to 99% of new hospitalizations in the US are unvaccinated individuals. Similarly, up to 99% of deaths from COVID-19 infections in the US are now in unvaccinated people.
  • Another analysis showed that a vaccinated 80-year-old patient is as likely as a non-vaccinated 50-year-old patient to survive the infection.

If you’re not already vaccinated, take the first chance you get. The best COVID-19 vaccine is the one that is available to you the soonest.


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About the Author:
Mersad Alimoradi is a medical doctor specializing in general surgery, with a big interest in academia. He is passionate about spreading medical knowledge and making it accessible to everyone. He has received his medical degree from the Lebanese University, in Beirut, and currently works as a physician and researcher in the country's university hospitals.

This article was updated on 1st August 2021. Updates include: 

  • Pfizer and BioNTech's request to the FDA to expand use of their COVID-19 vaccine to young adolescents.
  • Moderna vaccine distribution updates 
  • EMA’s update on AstraZeneca’s vaccine
  • Age limits for AstraZeneca’s vaccine
  • Covaxin Indian vaccine
  • Covishield Indian vaccine 
  • India's approval of the Russian vaccine Sputnik V COVID-19
  • Sinopharm's booster shot
  • The Johnson & Johnson vaccine pause due to rare blood clots.
  • CanSinoBIO’s new updates
  • 'Mix and match' UK Covid vaccine trial.



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