Vaccines are the human made weapons against the viruses and other microbial diseases that threatens the mankind. This Covid-19 pandemic is one of the worst of its kind as it reached each and every part of the world thus making the life of the people miserable. It impacted each and every person. It completely thrashed the economy of most of the countries, gave a strong blow and tremendously pressurized the medical systems of most countries, so it damaged the economic, social, mental and of course physical wellbeing of the mankind. It took thousands and thousands of lives, used many toddlers to be an orphan. Vaccines are probably the only effective weapon against this deadly war.

Vaccines contains the antigens in dead, inactivated or in other form that helps our body to produce immune response against it, thus tries to prevent the severity of the disease when exposed to the wilder version of the antigen. The smallpox vaccine was the first vaccine to be developed against a contagious disease by the British doctor Edward Jenner in 1796. Usually it takes a long time to develop vaccines. But Covid-19 vaccines are the vaccines that were produced in the least amount of time till now, this is a result of all the human intelligence when targeted against the single enemy-the virus.

What are the Stages of development for a covid-19 Vaccine?

The development of coronavirus vaccines consists of the following steps e.g. exploratory, pre-clinical and clinical stages.

1. Exploratory stage – It is the basic research in the laboratory of the conceptual idea and development of an antigen against the disease against which a vaccine needs to be produced which usually takes 2–4 years’ timeframe.

2. Pre-clinical stage of development – It uses a platform of tissue-culture and animal testing to assess the safety of the vaccine. They may also suggest the safest starting dose for the next phase of research as well as the safest method of administering the covid vaccine. This stage usually takes 1–2 years and out of 100 potential candidates, 6 usually pass through this stage.

3. Clinical stages of development – Consist of at least 3 stages and the 4th post-marketing safety assessment is also mandatory. These are performed on Human volunteers. 

• In Phase I, the main aim is to assess the safety as well the type of immune response the candidate vaccine may produce. The data is analysed and if it shows promising results, the trial progresses to the next phase.

• Phase II vaccine trial is randomized and well-controlled and includes a placebo group. The goals of Phase II clinical trial are to review the candidate vaccine’s safety, immunogenicity, proposed doses, schedule of immunisation and route of administration.

• In Phase III of the trial, the immunogenicity of the trial vaccine is tested, e.g. production of critical levels of antibodies/ cell-mediated immunity and whether it prevents infection by protecting from the disease.

• Phase IV: Many manufacturing companies undertake a Phase IV trial for safety, efficacy and other potential uses which are optional studies after a vaccine is released. 

Where do we stand in this vaccine race?

As of June 2021, 18 vaccines are authorized by at least one national regulatory authority for public use: two RNA vaccines (Pfizer–BioNTech and Moderna), nine conventional inactivated vaccines (BBIBP-CorV, Chinese Academy of Medical Sciences, CoronaVac, Covaxin, CoviVac, COVIran Barakat, Minhai-Kangtai, QazVac, and WIBP-CorV), five viral vector vaccines (Sputnik Light, Sputnik V, Oxford–AstraZeneca, Convidecia, and Johnson & Johnson), and two protein subunit vaccines (EpiVacCorona and RBD-Dimer).In total, as of March 2021, 308 vaccine candidates are in various stages of development, with 73 in clinical research, including 24 in Phase I trials, 33 in Phase I–II trials, and 16 in Phase III development.

Picture of Covid-19 Vaccines in India:

As of June 2021, three vaccines namely- Covishield, Covaxin, Sputnik V are being administered in India.

1. Covaxin

The DCGI gave the green signal to Hyderabad-based Bharat Biotech’s Covaxin in early January. Covaxin is an inactivated vaccine. It contains the dead virus, which prompts an immune response but doesn’t infect or make the person sick. It consists of two doses, given 28 days apart. Bharat Biotech and Ocugen jointly announced that Covaxin demonstrated efficacy of 80.6%in the Phase 3 trials. The vaccine can induce antibodies that can neutralize even the UK and Brazilian strains. Covaxin induces side effects including site pain, injection site swelling, injection site redness, injection site itching, stiffness in the upper arm, weakness in the injection arm, body ache, headache, fever, malaise, weakness, rashes, nausea, vomiting.

2. Covishield

India approved the Serum Institute of India’s (SII) Covishield vaccine in the first week of January 2021. The two-dose vaccine has been developed by SII in collaboration with Oxford University in the UK and AstraZeneca, a British-Swedish multinational pharmaceutical company. The Covishield is based on the viral vector platform. 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. The Indian government has recommended an interval of 8 weeks between the first and second doses of the vaccine. The peer-reviewed results of the Phase-III trials of the Covishield show that it is up to 90% effective. 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. It is effective against the UK strain and is being tested against the Brazilian variant too. Covishield does have a few side effects, such as pain, redness, itching and swelling or bruising, feeling unwell, fatigue, chills, fever, headache, nausea, joint pain, and muscle ache, but they are mostly mild to moderate in nature and can be treated with over-the-counter pills. It is also known to have triggered allergic reactions.

3. Sputnik V

Developed by the Russian medical research institute, Gamaleya Research Institute of Epidemiology and Microbiology, Sputnik V is the latest vaccine to be authorized for emergency use in India. Sputnik contains a vector is an engineered virus without the ability to replicate or multiply. When the vector containing the coronavirus gene is injected into the human body, it triggers a surge of coronavirus spike proteins without actually infecting the body. The body’s immune system then gears into high alert, making it capable of developing an immunity to the virus. It follows a two-dose regimen over a gap of 28 days. Manufacturers of the Sputnik V vaccine has released a statement detailing an impressive 95 percent efficacy rate observed in volunteers 42 days after the first dose, that is 21 days after the second dose. No unexpected adverse events were identified as part of the research. Some of those vaccinated had short-term minor adverse events such as pain at the injection point and flu-like symptoms including fever, weakness, fatigue, and headache.