A year of uncertainty, 2020, when the whole world got clouded by an unprecedented health crisis in the form of Covid-19 pandemic, an urgent international response to prepare for an outbreak got triggered in the form of social distancing, sanitation measures and compulsory mask wearing. As is said ‘well begun is half done’, all it needed to complete the fight against the deadly virus was to be ahead of the virus and make a safe and efficacious vaccine. Vaccine is a biological preparation that constitutes the cornerstone therapy in the management of particular infectious diseases. On a broader aspect, vaccines can either be prophylactic (to prevent or ameliorate the effects of a future infection by a natural or “wild” pathogen), or therapeutic (to fight a disease that has already occurred, such as cancer). In an ideal world, all vaccines would induce sterilizing immunity, meaning thereby that the vaccine not only prevents one from getting a disease but also an infection. However, in real world it is actually difficult to produce vaccines that stop infection altogether. As Covid-19 pandemic became a Public Health Emergency of International Concern, the scientific minds across the globe got together, decoded the genetic sequence within a month’s time and hastened the development of a preventive/ prophylactic Covid-19 vaccine.
As of January 2021, nine different technological platforms were under research with main focus being upon the corona virus spike protein and its variants. It ultimately lead to the development of four distinct types of Covid vaccines worldwide — whole virus (attenuated or weakened form), protein subunit, nucleic acid (RNA or DNA) and viral vector. However, India, that was at the forefront of the COVID-19 vaccination race right from the early stages of the pandemic developed the two vaccines — Covishield and Covaxin and gave an Emergency Use Authorization (EUA) approval without added conditionalities, although the latter was recommended to be administered in a ‘clinical trial mode’. In the history of human race it must be for the first time that within a span of one year the vaccines were manufactured with a satisfactory efficacy minus the major side effects.
The Covishield vaccine manufactured by Serum Institute of India, Pune uses the master seed of Oxford-AstraZeneca vaccine, that is, a viral vector platform, technology previously used to prepare vaccines for Ebola virus. In simple terms, it is made from a weakened version of a common cold virus, called adenovirus, from chimpanzees and has been modified to look more like coronavirus. After vaccination, the surface spike protein is produced, priming the immune system to attack the SARS-CoV-2 virus if it later infects the body. It can be stored, transported and handled at normal refrigerated conditions (2°C-8°C/ 36°F-46°F) and has a shelf-life of at least six months. The peer-reviewed results of the Phase- III trials have shown an efficacy and effectiveness of up to 90%. However, the results also revealed that the vaccine was only 62% effective when participants were given two full doses, but its efficacy rose to 90% when a half dose followed by a full dose was administered. Besides some problems earlier in South Africa recently it has not been used in 8 European Nations including Italy, Denmark, and Norway etc. for fear of serious blood clot incidents. Hence, we have to observe its process with an Eagle Eye.
The Covaxin, on the other hand, has been developed by Hyderabad-based Bharat Biotech in association with the Indian Council of Medical Research (ICMR) and the National Institute of Virology (NIV). This vaccine is developed with Whole-Virion Inactivated Vero Cell-derived technology and is an inactivated vaccine (using a chemical called, beta-propiolactone), prepared on a tried and tested platform of dead viruses, which prompts an immune response but doesn’t infect or make the person sick. There are many inactivated vaccines already in use against various diseases like Hepatitis A, Influenza, Polio, Rabies, which offer “excellent protection”. The two dose Covaxin has been found to be 81% effective in an interim analysis of late stage trial data on about 26,000 people with 10- 12% less side effects when compared with other Covid- 19 vaccines. Since Covaxin contains the whole body of a virus instead of just its ‘spike protein’ tip, it has the potential to work against other Covid-19 variants, is likely to be safer in children over the age of 12 years and could be used as a booster for people already vaccinated with a first dose of other shots.
Although the country’s national vaccination program has entered into the 2nd phase, only 2 % of the population has been inoculated with the vaccine till date. This vaccinated percentage seems to be a miniscule as we are aiming at the realistic population vaccination coverage rate of 75% so as to prevent an epidemic or extinguish it without further measures such as social distancing. The one reason that holds the public from taking a jab seems to be a misperception about its safety and efficacy. This Vaccine hesitancy might prove to be a global health threat as it will increase the risk of further viral spread leading on to intermittent flare up of Covid-19 outbreaks.
Almost all existing vaccines drastically reduce the odds of hospitalisation or death due to Covid-19 and in light of the present situation, what matters the most is to get inoculated against the corona virus irrespective of which vaccine has been administered. There are the potential vaccines in pipeline in form of nasal spray or single shot regimen that might prove to be the game changer and fare better than the current ones but waiting for a better vaccine would be a potentially lethal mistake. Even a partial, late, or weak immunity, such as a one resulting from cross-immunity to a strain other than the target strain, may mitigate an infection, resulting in a lower mortality rate, lower morbidity and faster recovery.
At an individual level each citizen should behave responsibly by taking the jab and promote the co citizens to do the same, at the policy level the bureaucratic hurdles need to be softened and smoothened with involvement of multiple other sectors for example — defence forces, paramilitary forces, railways, airlines, judiciary, corporates, other private and semi-private organisations so that maximum people get vaccinated at an earliest. The only best way forward in present scenario is to register yourself and get vaccinated as soon as possible, regardless of Covishield or Covaxin.
Dr. Pawan Suri
SGL SuperSpeciality Hospital
Email; [email protected]