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What are the stages in the development of a covid-19 vaccine? 

1.Firstly, a replacement vaccine candidate has  to pass testing on animals. 

2.Following which clinical trials is the next step. 

3.Then, over three phases, the vaccine candidate’s safety and efficacy are tested.

4. A fourth stage involves and analysis of post-marketing data.

 

Pre-clinical tests 

During this primary stage, scientists test the vaccine on animals like mice or monkeys to ascertain if it produces an immune reaction. 

Phase I trials

This is often the primary step where the experimental vaccine is given to humans, usually between 20-80 subjects, to check safety and dosage and check whether it stimulates the system and produce antibodies. 

Aim

• How much of the drug is safe to give

• What the side effects are

• If the treatment helps 

Phase II trials 

During this  stage, a bigger group of several hundred individuals are enrolled for testing and that they are split into groups age-wise like children and elderly. The phase II clinical trial testing studies the candidate vaccine’s safety, immunogenicity, proposed doses, schedule of immunisations and method of delivery. 

Aim

• If the new treatment works well enough to be tested in a larger phase 3 trial.

• More about side effects and how to manage them

• More about the best dose to use.

Phase III trials

 Since certain side effects might not be seen within the smaller groups of humans tested in earlier phases, the vaccine candidate is given to thousands of individuals during this stage. These trials can determine if the vaccine protects against the coronavirus. 

 

Aim

• Which treatment works better for a particular type.

• More about the side effects

• How the treatment affects people’s quality of life

• more about the side effects and safety of the drug

• What the long term risks and benefits are

• How the drug can be used widespread.

Approval

 After phase III clinical trial trials, the vaccine developer submits a license application to the regulatory agency in their respective country. The regulator then inspects the factory where the vaccine are going to be made and approves its labeling. 

What sorts of Covid-19 vaccines are being developed? 

With limited time , scientists are developing some vaccines from scratch and a few from existing molecules developed for other diseases. What has aided the research is that the incontrovertible fact that the novel coronavirus is from a family on which work is already being done worldwide after SARS and MERS. 

Geneticvaccines: These are the vaccines that use the genes of the coronavirus (in the shape of DNA or RNA) to impress an immune reaction.

 Viral vector vaccines: Thevaccines use an epidemic to deliver coronavirus genes into cells and provoke an immune reaction. These viruses are weakened in order that they cannot cause disease.

Protein-based vaccines: These vaccines use a coronavirus protein or a protein fragment to impress an immune reaction by mimicking the coronavirus outer coat.

 

Whole virus vaccines: Such vaccines use a weakened virus. These vaccines are created by inactivating a pathogen, typically using heat or chemicals. This destroys the pathogen’s infectivity while retaining immunogenicity.

 

Which Covid-19 vaccines are the highest contenders and have shown promise?

 Even though most of the over 120 vaccines under development are undergoing phase II clinical trial clinical trials, only two of them are in combined Phase II/III trials. 

1. Oxford-AstraZeneca vaccine (Phase II/III) 

The vaccine, supported a chimpanzee' virus called adenovirus. In beginning Phase II/III testing within the UK and Brazil. 

2. Moderna vaccine (Phase II) 

US firm Moderna Inc is developing a vaccine, using messenger RNA to supply viral proteins. Final-stage trials of the vaccine on people and therefore the firm hopes to possess vaccine doses ready by early 2021. Studies in mice has lent some assurance that it's going to not increase the danger of more severe disease. 

3. Pfizer-BNTECH vaccine (Phase II)

 Pfizer, which is co-producing a Covid-19 vaccine , has started the method of dosing patients. Pfizer believes that a Covid-19 vaccine might be ready by the top of October 2020. 

4. Imperial College London vaccine (Phase II)

 The vaccine candidate developed is predicated on self-amplifying RNA technology . Imperial hopes the vaccine might be available by october.

 

5. Sinovac Biotech vaccine (Phase II) 

The company is testing an inactivated vaccine called CoronaVac and is preparing phase III clinical trial trials. Preliminary findings from phase I clinical trial and II trials have shown that its shot is safe and capable of obtaining an immune reaction from human trials. 

6. Novavax vaccine (Phase II) 

US biotechnology company Novavax has done its vaccine’s testing for Covid-19. The results of the primary phase of clinical trials are expected to be known in July following which thousands of candidates in several countries would then get entangled during a second phase. Animal testing suggested the recombinant vaccine is effective in low doses.

 

7. Sinopharm vaccine (Phase II) Sinopharm, is planning late-stage human trials in foreign countries. It recently said its experimental coronavirus vaccine has triggered antibodies in April . 

8. CureVac vaccine (Phase I) 

CureVac has started human trials of its coronavirus vaccines, the firm is employing a new technology supported mRNA, a kind of genetic material never before wont to make a vaccine. 

9. Johnson & Johnson vaccine (Phase I) Johnson & Johnson has the started human clinical trials for its recombinant vaccine by two months to the last half of July.