Which Covid-19 vaccine is the best bet?

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COVID-19 vaccine trial results of Moderna, Pfizer, Oxford or Sputnik have arrived

Festivals do bring cheer in everyone’s life. This year, it brought something more, which raised optimism  in the “Corona era”. Man is a social animal and Corona has deprived us of that very special character. Hope to get that back soon with the most awaited “star” report card of COVID-19 preventive vaccines. Until everyone gets access to vaccines, we will have to follow all safety norms, “Do Gaj kee doori aur mask hai Zaroori”,  strictly for few months at least!!

November started with pouring in of optimistic results  from various vaccine making companies.

Pfizer and BioNTech press release for COVID-19 vaccine

Pfizer and BioNTech  were the first ones to issue their press release on November 18th. Their product BNT162b2, a new age RNA vaccine, has demonstrated ~ 95% efficiency against symptomatic  COVID-19  virus infection. Pfizer claimed that the vaccine’s efficacy was same across people of all age groups, genders, races and ethnic origins. They have so far achieved the safety data milestone required by U.S. Food and Drug Administration (FDA) for Emergency Use Authorization (EUA) in USA. If FDA gives the authorization, Pfizer vaccine could be used in high-risk populations in the U.S. by the end of December 2020. Minor side effects like fatigue, headache and fever were reported but there were no serious safety concerns.

Pfizer and BioNTech have taken up the humongous task to produce ~ 50 million vaccine doses in 2020 and scale up to 1.3 billion doses by the end of 2021 to provide the vaccines globally.

Technology behind Pfizer COVID-19 vaccine

cold storage

Pfizer vaccine is developed by advance mRNA technology that utilizes the genetic code of the COVID-19 virus. Due to this, concerns like, “What will happen to vaccine effectiveness  if the SARS-CoV-2 virus mutates?” can be addressed fast. Researchers can simply modify the genetic code if the virus mutates.

Everything looks amazing except the vaccine’s high maintenance nature. The RNA vaccine needs to be kept at ultra low temperatures (-80⁰C) throughout its journey from the factory to the clinic, where it will be administered. This requires heavy investment for cold storage infrastructure and does not seem feasible in developing and poor parts of world.

Moderna press release for COVID-19 vaccine

mrna vaccine moderna

Another RNA vaccine by Moderna located at Cambridge Massachusetts, reported 94% efficacy in preventing COVID-19. The Moderna release shared results from analysis of 95 cases in the ongoing phase III efficacy trial. mRNA-1273 is an mRNA vaccine against COVID-19 encoding for Spike (S) protein. It was co-developed by Moderna and investigators from NIAID’s Vaccine Research Center. There were no significant safety concerns other than fatigue, muscle pain and headaches, which occurred in 1 person out of 10 people vaccinated. Moderna vaccine has an edge over Pfizer vaccine in being stable at  2° to 8°C (36° to 46°F), the temperature of a standard home or medical refrigerator, for 30 days. mRNA-1273 remains stable at -20° C (-4°F) for up to six months, and at room temperature for up to 12 hours.

Gamaleya press release for COVID-19 vaccine

sputnik 2 vector

Good news didn’t stop at this. Sputnik V, the Covid-19 vaccine from Russia, has reported an efficacy of over 95%. Sputnik V is a unique vaccine as it is a 2 vector vaccine, employing adenoviruses. It is developed by Gamaleya Institute and RDIF (Russian Direct Investment Fund) and may be priced under $20 per person for the two doses globally, including India. It is actually expected to be twice as cheap as vaccines by Pfizer and Moderna with similar positive results. The vaccine can be accepted to be administered in India after scheduled phase II and III trials from December to April. It will be manufactured by Indian companies. Hyderabad-based Dr. Reddy Lab and Russian Direct Investment Fund (RDIF) have done the contract for clinical trials and production of vaccine for India. Sputnik came under controversy when Russian Govt. approved it early without sufficient testing. Sputnik V vaccine comes with one challenge for sure despite its cheap price. It requires a specialized cooling chain to maintain temperature at -20 degrees C. But, still it has an edge over Pfizer vaccine which needs to be stored at -80 degrees C. As part of the partnership, RDIF will give 100 million doses of the vaccine to Dr Reddy’s lab.

Oxford press release for COVID-19 vaccine

Promising results have come from another highly sought after vaccine by Oxford and AstraZeneca combined efforts. Oxford vaccine reported an average efficacy of 70 percent in preventing symptomatic Covid-19 disease. The results looks quite disheartening at first impression in comparison to Pfizer, Moderna and Russian vaccines. The twist in the tale comes from the claim by researchers that the results were actually an average of two kinds of dosing regimen. Interestingly, 90% effectiveness was obtained when a half dose was followed by the full dose after one month. Another dosing regimen comprised of 2 full doses one month apart and showed 62% efficacy. The combined result gave ~70 % efficacy.

Why is less better than more?

The possible explanation to this can be that the immune response is also generated against the Adenovirus vector used in vaccine and the first full dose may overshadow the actually needed immune response against spike proteins of COVID-19 virus. Another possible reason of getting higher efficacy with half dose may be that it was given to younger volunteers, who anyway gain higher immune response due to age factor than older volunteers. But all these assumptions are hard to swallow and needs further research leading to vaccine’s dosage adjustment and final acceptance.

astrazeneca lab

Technology behind Oxford vaccine

The popularly called Oxford vaccine (ChAdOx1 nCoV-19) is made from an attenuated or weakened cold causing adenovirus.  It can’t replicate in human cells but can work as a vector to shuttle a gene from SARS-CoV-2 that causes COVID-19, into our bodies. Our genes can then synthesize Coronavirus spike proteins and train our body to recognize the real COVID-19 infection in future and act promptly. This technique is being researched for more than 3 decades to develop vaccines.

Indian connection to Oxford COVID-19 vaccine

Serum Institute of India (SII), the world’s largest producer of vaccines has joined hands with AstraZeneca to produce the Oxford vaccine in the brand name Covishield. Adar Poonawalla stated that Covishield will be low cost, highly effective, widely available vaccine without any serious side effects. SII is geared to make 100 million doses by January for mass vaccinations across India. Covishield will be available in market at Rs. 500-600 per dose and at Rs. 220-300 for the government. It is cheaper than other vaccines by Pfizer and Moderna which may be priced at $20 or Rs. 1,500 per dose and  $37 or Rs. 2,775 per dose respectively.

Covishield has better prospects than other COVID-19 vaccines

Simpler supply chain, scalable platform and ease of storage at normal refrigerator temperatures  are pluses of Oxford vaccine. Extra cost to build sub zero cooling chain while transportation and administration is not required for Covishield, which makes it a star vaccine for remote areas as well.

Other promising COVID-19 vaccine we are waiting for

One more promising  COVID-19 vaccine candidate is Covaxin by Bharat Biotech International Limited in partnership with the Indian Council of Medical Research (ICMR).  It has reached Phase 3 trial stage. Clinical trials will be done at 26,000 participants in 130 centers across the country. It is the first purely indigenous candidate to reach this stage till now and will surely make the nation “Atmanirbhar” to tackle Covid situation with its success soon.

The other two potential candidates are Cadila’s experimental vaccine that is going to complete Phase 2 trials soon and a candidate by Biological E that is going to enter Phase 2.

volunteer vaccination

Vaccine hunt may have given good results but how far are we in actually getting the COVID-19 vaccine?

Despite many high ranking COVID-19 vaccine candidates, we still may have to continue living like we have been living since the first lock down happened in the country. Cases are rising at an alarming speed throughout the country. The results may look convincing to countrymen but it is hard to lure critics, renowned scientists and India’s National Regulatory Authority (NRA). Vaccine companies may have hastily published the results from their still incomplete trials or may have shown some positive results only, hiding unfavorable results like side effects and efficacy complete data sets. There are other logistics also like procurement, storage, transfer and handling etc involved in making the vaccines available for final mass immunizations. All these might take at least half of the year 2021 even if things go smoothly without any glitches. So India, please have patience in starting your social activities like marriages, religious ceremonies, festivals etc. with full grandeur and no safety.  Safety primarily comes with the responsibility of each citizen towards themselves, their family and nation as a whole. Social distancing, hand sanitation and proper use of masks are the best bet in preventing severe COVID-19 infections for now.


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