Modern COVID-19. Vaccines. Kimberly Meg Pereira (ОрГМУ) 309и

Overview
COVID-19 pandemic has resulted in millions of deaths and a social-economic crisis.
A worldwide effort was made to develop efficient vaccines for this disease.
A COVID‑19 vaccine is a vaccine intended to provide acquired immunity against severe acute respiratory syndrome coronavirus 2 (SARS‑CoV‑2), the virus that causes coronavirus disease 2019 (COVID‑19).

Stages of Vaccine Development
Vaccine design involves the selection of platforms that includes viral, viral-vector, protein, nucleic acid, or trained immunity-based strategies. Its development initiates at a pre-clinical stage, followed by clinical trials when successful. Only if clinical trials show no significant evidence of safety concerns, vaccines can be manufactured, stored, and distributed to immunize the population.
So far, regulatory authorities from many countries have approved nine vaccines with phase 3 results.

List of COVID-19 Vaccines
Moderna. mRNA-1273.
Pfizer/BioNTech. BNT162b2.
Janssen (Johnson & Johnson) Ad26.COV2.S.
Oxford/AstraZeneca. AZD1222.
Sputnik-V (Gam-COVID-Vac)
Serum Institute of India. Covishield (Oxford/AstraZeneca formulation)
Sinopharm (Beijing) BBIBP-CorV (Vero Cells)
Sinovac. CoronaVac.
Novavax (NVX-CoV2373) *
*This vaccine is in Phase 3 trials and has not been authorized by any country.

Vaccine Types (against COVID-19) and their Characteristics

Some Vaccine Types and Their Popular Examples
mRNA vaccines
Pfizer–BioNTech
Moderna
Adenovirus vector vaccines
Oxford–AstraZeneca
Sputnik V
Janssen
Subunit vaccines
EpiVacCorona
Novavax COVID-19 vaccine,
Inactivated coronavirus vaccines
China: CoronaVac, BBIBP-CorV, and WIBP-CorV
India: Covaxin
Russia: CoviVac
Additional types of vaccines that are in clinical trials include virus-like particle vaccines, multiple DNA plasmid vaccines, at least two lentivirus vector vaccines, a conjugate vaccine, and a vesicular stomatitis virus displaying the SARS‑CoV‑2 spike protein.

Overview of some COVID-19 vaccines

Pfizer-BioNTech
Type: mRNA vaccine
For ages: People 12 years and older
Number of Shots: 2 shots Given 3 weeks (21 days) apart
When Fully Vaccinated: 2 weeks after your second shot
Additional Dose: Recommended for moderately to severely immunocompromised people, given 4 weeks after second shot
Booster Dose: Recommended for some people who are at higher risk for COVID-19 exposure or severe illness , given 6 or more months after second shot
Efficiency: 95%
Common side effects: Chills, headache, pain, tiredness, and/or redness and swelling at the injection site, all of which generally resolve within a day or two of rest, hydration, and medications like acetaminophen. On rare occasions, the vaccine has appeared to trigger anaphylaxis.
As far as the Delta variant, two studies reported by Public Health England that have not yet been peer reviewed showed that full vaccination after two doses is 88% effective against symptomatic disease and 96% effective against hospitalization.

Moderna
Type: mRNA vaccine
For ages: People 18 years and older
Number of Shots: 2 shots given 4 weeks (28 days) apart
When Fully Vaccinated: 2 weeks after your second shot
Additional Dose: Recommended for moderately to severely immunocompromised people, given 4 weeks after second shot
Booster Dose: Not recommended at this time
Efficiency : 94%
Common side effects: Chills, headache, pain, tiredness, and/or redness and swelling at the injection site, all of which generally resolve within a day or two. On rare occasions, it has appeared to trigger anaphylaxis
In June 2021, Moderna reported that studies showed its vaccine is effective against the Beta, Delta, Eta, and Kappa variants, although it did show it to be about two times weaker against Delta than against the original virus.

Johnson & Johnson’s Janssen
Type: Adenovirus viral vector vaccine
For ages: People 18 years and older
Number of Shots: 1 shot
When Fully Vaccinated: 2 weeks after your shot
Additional Dose: Not recommended at this time
Booster Dose: Not recommended at this time
Efficiency: 64.7%
Common side effects: Fatigue, fever headache, injection site pain, or myalgia (pain in a muscle or group of muscles), all of which generally resolve within a day or two. It has had noticeably milder side effects than the Pfizer and Moderna vaccines, according to the FDA report released in late February. No one suffered an allergic reaction in clinical trials for the vaccine, according to the company.
Johnson & Johnson reported effectiveness against the Delta variant, showing only a small drop in potency compared with its efficacy against the original strain of the virus, although one recent study suggested that the J&J vaccine is less effective against Delta.

Covishield
Type: Viral vector vaccine
For ages: People 18 years and above
Number of shots: 2 doses
Efficiency: 81.3 %
Common side effects : Tenderness, pain, warmth, redness, itching, swelling or bruising at the injection site, all of which generally resolve within a day or two. Rare complication are blood clots.
As far as the Delta variant, two recent studies (neither has been peer-reviewed) showed, respectively, that full vaccination after two doses is 60% effective against symptomatic disease and 93% effective against hospitalization.

Sputnik V
Type: Adenovirus viral vector vaccine
For ages: People 18 years and above
Number of shots: 2 shots given 3 weeks (21 days) apart
When Fully Vaccinated: 2 weeks after second shot
Efficiency: 91.6 %
Side effects: Pain, redness, or swelling at the site of injection, Asthenia (lack of energy / abnormal physical weakness), Fatigue, Body and muscle pain, Cough and Sore throat, Runny nose, Fever and Chills, Nausea and Vomiting , Diarrhea, Headache
Sputnik V is around 83% effective against the Delta variant of coronavirus, according to the latest studies

Mechanism of Action
Sputnik V (Gam-COVID-Vac) is based on safe and effective human adenovirus vector platform using two different adenoviral vectors - Adenovirus 26 (Ad26) and Adenovirus 5 (Ad5) as an expression of SARS-CoV-2 spike protein gene.

Immune Response graph after administration of Sputnik V

Conclusion
COVID-19 vaccines are crucial tools in the pandemic response and protect against severe disease and death. Vaccines provide at least some protection from infection and transmission, but not as much as the protection they provide against serious illness and death.
Vaccines are likely staying effective against variants because of the broad immune response they cause, which means that virus changes or mutations are unlikely to make vaccines completely ineffective.
One of the best ways of guarding against new variants is to continue applying tried-and-tested public health measures and rolling out vaccines.