Now the different parts of world is facing the third wave of the Covid-19. It has a higher case fatality rate and unknown route of transmission. Worldwide scientists were worked hard in researching new vaccine. After untiring efforts more than a dozen vaccines now have been authorized around the globe; many more remain in development.
National regulatory authorities have granted emergency use authorizations for fourteen Covid-19 vaccines. Six of those have been approved for emergency or full use by at least one WHO-recognized stringent regulatory authority (Oxford–AstraZeneca, Pfizer-BioNTech, Sputnik V, Sinopharm-BBIBP, Moderna, and Johnson & Johnson).
The Vaxzevria – AstraZeneca COVID-19 (AZD1222) (ChAdOx1 nCov-19) (C19VAZ) coronavirus vaccine is made from a virus (ChAdOx1), a weakened version of a common cold virus (adenovirus). Genetic meterial has been added to the ChAdOx1 construct, which is used to make proteins from the SARS-CoV-2 coronavirus called Spike glycoprotein (S).This protein is usually found on the surface of SARS-CoV-2 and plays an essential role in the infection pathway of the SARS-CoV-2 virus.
Vaxzevria/covishield vaccine is adviced more in people aged 18 years and older.People with a history of severe allergic reaction to any component of the vaccine should not take it. The recommended dosage is two doses given intramuscularly (0.5ml each) with an interval of 8 to 12 weeks. It has an efficacy of 63.09% against symptomatic SARS-CoV-2 infection.
The Pfizer–BioNTech COVID-19 vaccine, sold under the brand name Comirnaty, is an m-RNA-based covid-19 vaccine. It is given by intramuscular injection. It is composed of nucleoside modified mRNA (modRNA) encoding a mutated form of the full-length spike proteinof SARS COV-2, which is encapsulated in lipid nanoparticles.
The vaccine has only been tested in children above 16 years of age. Therefore, WHO does not recommend vaccination of children below 16 years of age before.
The CDC’s Advisory Committee on Immunization Practices recommend that Pfizer/BioNTech’s Covid vaccine be administered to 12- to 15-year-old adolescents, following an FDA decision on May 12, 2021 Wednesday to expand the vaccine’s Emergency Use Authorization to include this age group.
The dose and the schedule are the same; the two shots are given three weeks apart.
A protective effect starts to develop 12 days after the first dose, but full protection requires two doses which WHO recommends be administered with a 21 to 28-day interval.
3. Sputnic V
Russia’s Sputnik V also known as Gam-COVID-Vac, is an adenoviral vector-based vaccine in which adenovirus serotypes 5 and 26 are used.It is the first registered vaccine against COVID-19.Sputnik V uses a weakened virus to stimulate an immune response.
Sputnic V is available in a lyophilized (dry) form of the vaccine that significantly facilitates the logistics of its distribution in international markets due to simplified requirements for its storage temperature (+ 2 – 8 degrees Celsius).
Sputnik vaccine is indicated for active immunization to prevent COVID-19 disease in individuals of ≥ 18 years of age and indicating 91.6% efficacy without unusual side effects. The developers says this 2 dose vaccine has 21 days to 3 months of interval.
BBIBP-CorV, also known as the Sinopharm New Crown COVID-19 vaccine,is an inactivated vaccine made of virus particles grown in culture and lack disease-producing capability.
BBIBP-CorV,was developed by Sinopharm’s Wuhan Institute of Biological Products Co. and the Chinese Center for Disease Control and Prevention (CDC).
It has an aluminum hydroxide adjuvant and packed into prefilled syringes in 0.5-mL sterile phosphate-buffered saline without preservative, and the vaccine is given intramuscularly in two doses 28 days apart. Sinopharm showed that it had an efficacy rate of 79 percent.In phase I/II placebo-controlled randomized trials of healthy individuals 18 to 80 years old, all recipients of two vaccine doses developed neutralizing and binding antibodies
The Moderna covid 19 vaccine(mRNA 1273) is an mNRA-based vaccine.The mRNA in the vaccine is embedded in lipid nanoparticles that enable delivery of the RNA into host cells to allow expression of the SARS-CoV-2 spike (S) antigen. The vaccine elicits both neutralizing antibody and cellular immune responses to the S antigen, which may contribute to protection against COVID-19 disease.
This vaccine is produced by the American company Moderna, the U.S. National Institute of allergy and infectious diseases, the U.S. Biomedical Advanced Research and Development Authority, and the Coalition for Epidermic Preparedness Innovation.
The Moderna covid 19 vaccine is administered in two intramuscular doses of 0.5 mL each, given one 28 days apart. The vaccine is recommended for people aged 18 years and older.
Based on evidence from clinical trials, the Moderna vaccine was 94.1% effective at preventing laboratory-confirmed COVID-19.
Covaxin the covid 19 vaccine is developed using Whole-Virion Inactivated Vero Cell derived platform technology. Inactivated vaccines do not replicate and are therefore unlikely to revert and cause pathological effects.It is included along with immune-potentiators, also known as vaccine adjuvants, which are added to the vaccine to increase and boost its immunogenicity.
Covaxin is an India‘s indigenous COVID-19 vaccine developed by Bharat Biotech in collaboration with the Indian Council of Medical Research (ICMR) – National Institute of Virology (NIV).
It is a 2-dose vaccination regimen given 28 days apart.The vaccine can be stored at 2C to 8C.It is authorised to administer for age above 12 years. COVAXIN demonstrated 81% interim efficacy.
7. Corona Vac
CoronaVac, also known as the Sinovac COVID-19 vaccine,developed by Sinovac Life Sciences, Beijing, China.
It is an inactivated virus COVID-19 vaccine and mixed them with a tiny amount of an aluminum-based compound called an adjuvant. Adjuvants stimulate the immune system to boost its response to a vaccine. CoronaVac works by teaching the immune system to make antibodies against the SARS-CoV-2 coronavirus. The antibodies attach to viral proteins, such as the so-called spike proteins that stud its surface.
The vaccine is given intramuscularly in two doses 28 days apart. In a phase I/II randomized, placebo-controlled trial, the vaccine appeared safe and immunogenic in healthy individuals aged 18 to 59 years.
8. NVX-CoV2373 (Novavax)
NVX-CoV2373 (Novavax) is a recombinant protein nanoparticle vaccine composed of trimeric spike glycoproteins and a potent Matrix-M1 adjuvant. The vaccine is given intramuscularly in two doses 21 days apart. In a phase I/II randomized, placebo-controlled trial of healthy individuals <60 years old, the adjuvanted vaccine induced high binding and neutralizing responses, comparable to those in convalescent plasma from patients who had been hospitalized with COVID-19. CD4 cell responses with a Th1 bias were also detected.
9. Johnson & Johnson’s Janssen COVID-19 Vaccine
Ad26.COV2.S(Trade name : Janssen) vaccine is based on a replication-incompetent adenovirus 26 vector that expresses a stabilized spike protein. It is given intramuscularly and is being evaluated as a single dose. An unpublished report from a phase I/II randomized, double-blind, placebo controlled trial described high rates of neutralizing and binding antibodies after a single vaccine dose in healthy individuals 18 to 85 years old; these responses overlapped with but were slightly lower than those in convalescentplasma. Fewer than one percent reported severe systemic reactions. CD4 cell responses with a Th1 bias were also detected.
Recombinant Novel Coronavirus Vaccine (Adenovirus Type 5 Vector) (“Ad5-nCoV”, trade name: Convidecia) is a single-dose viral vector vaccine for COVID-19 developed by CanSino Biologics,China.
Convidecia is similar to other viral vector vaccines produced by AstraZeneca (AZD1222), Sputnick V (Gam-COVID-Vac), and Ad26.COV2.S.
Vaccines provide timely mass protection for adults aged 18 and above, including those over 60. Safe, stable storage and transportation between 2°C and 8°C, accessible by under-developed regions.
the vaccine had an efficacy of 65.7% at preventing moderate cases of Covid-19 and 90.98% efficacy at preventing severe cases.
11. Epi Vac Corona Vaccine
EpiVacCorona is an peptide antigens-based vaccine conjugated to a carrier protein and adsorbed on an aluminum-containing adjuvant (aluminum hydroxide), that provokes an immune reaction against COVID-19 and promotes the further development of immunity.it does not contain the live virus.
EpiVacCorona is developed by the Vektor State Research Center of Virology and Biotechnology in Russia.
The vaccine delivered via intramuscular route twice.
12. RBD Dimer
RBD-Dimer is an adjuvanted protein subunit covid-19 vaccine developed by the Institute of Microbiology at the Chinese Academy Sciences. The CoV spike receptor-binding domain (RBD) is an attractive vaccine target for coronaviruses but is constrained by limited immunogenicity, however a dimeric form of MERS-CoV RBD offers greater protection. The RBD-dimer significantly increases neutralizing antibodies compared to a conventional monomeric form.