COVID-19 Vaccines

COVID-19 Vaccines COVID-19 pandemic The current global pandemic is caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The novel virus was identified in Wuhan, China. There have been numerous outbreaks of the virus since 2021, with the Delta, Alpha, and Beta varieties the most virulent. As of 27 July 2021, COVID-19 has caused more than 196 million confirmed cases, with more than 4.18 million confirmed deaths, making it the deadliest pandemic in history. The Chinese government reports using reverse transcription-polymerase chain reaction (RT-PCR) to diagnose COVID-19. COVID-19 Vaccines and their efficacy These drugs are being used as COVID-19 vaccines: Covaxin, Covishield, Moderna, Sputnik V, Sinovac, Johnson & Johnson, AstraZeneca and Pfizer. It is restricted to a specific population. In comparing the effectiveness of Covaxin, Covishield, and Sputnik, Covaxin ranked at 81%, while Covishield was at 90%, and Sputnik was at 91.6%. Sinovac and Sinopharm: It produce inactivated virus vaccines that prevent symptoms of Covid infection 50%-79% of the time. Pfizer: 95 % of people without prior infections can avoid infection. Moderna: 94.1% of people with no previous history of Coronavirus infection are prevented from developing an asymptomatic infection. Johnson & Johnson: Overall efficacy is 72% and resistance to severe illness is 86%. AstraZeneca: Against severe diseases, both doses are 100% effective in reducing disease symptoms. As well as 86 percent effectiveness in preventing Coronavirus infections, the company has also claimed that the product prevents infections among over 65 years. A review of the efficacy of COVID-19 vaccines SARS-CoV-2 Variants: SARS-CoV-2 is currently spreading globally in several variant forms. Around the world, Covid comes in thousands of different variants. Some countries, including the UK, appear to be experiencing a more rapid spread of Delta, also known as B.1.617.2. Most widely present today, sharing the more transmissible mutation D614G, are: 1. The Alpha variant, B.1.1.7, has been detected in over 120 countries since it was discovered in UK and has begun to mutate again. 2. The Gamma variant, P.1, has been detected in over 50 countries since it was discovered in Brazil. 3. The Beta variant, B.1.351, has been detected in over 80 countries since it was discovered in South Africa.

4. The Delta variant, B.1.617.2, has been detected in over 70 countries since it was discovered in India. How are the mutants behaving? 1. The spike protein - which attaches the virus to human cells - has all been altered in all the variants of concern. Some Delta properties may be important (such as L452R) that could further its spread. No evidence exists indicating that it increases disease severity or renders current vaccines ineffective. 2. A key mutation, called E484K is present in Beta and Gamma that may allow the virus to avoid the body's immune system. 3. The virus appears to be better at infecting cells and spreading when it has a mutation known as N501Y, found in the Alpha, Gamma, and Beta strains. Alpha variant 1. Novavax vaccine was efficacious against Alpha at 86%, and symptoms against the original variants at 96%. 2. Oxford-AstraZeneca vaccine was efficacious against Alpha at 42–89%, and against the other variants at 71–91%. Beta variant In March 2021, the Novavax vaccine (NVX-CoV2373) can effectively prevent COVID-19 in HIV-negative participants who have mild, moderate, or severe symptoms. Since it has preliminary efficacy of 51%. Gamma variant Reviewed by the WHO, there are limited data regarding CoronaVac and BBIBP-CorV, and no studies have yet been conducted for other vaccines, which suggests that there is likely retained efficacy against disease from Gamma. To prevent asymptomatic infection from vaccines, Oxford–AstraZeneca, and CoronaVac have demonstrated that they also retain neutralization against Gamma (no to minimal reduction), but slightly reduce neutralization from Pfizer– BioNTech and Moderna (minimal to moderate reduction). Delta variant Pfizer vaccines are 88% effective from the delta variant, 93.7% effective against the alpha variant. How effective is vaccines against COVID-19 variant? Vaxzevria vaccine: The effectiveness of Vaxzevria against the beta/gamma variants of SARS-CoV-2 was 82%. The vaccine proved highly effective against the Delta (B.617.2) and Alpha (B.1.1.7) variants with an 87% and 90%. Beta/Gamma vaccines were 50% effective against the symptomatic disease, and Delta and Alpha vaccines were 70% and 72% effective. Moderna vaccine:

One dose of Moderna’s mRNA-1273 vaccine was 94% effective at the same interval. The results show that the two-dose vaccination regimen of mRNA vaccines provides 88% protection against non-variant virus, 86% against the Alpha variant and 77% against the Beta variant. AstraZeneca’s Vaxzevria vaccine: It is 82% effective in preventing hospitalization or death from the Beta and Gamma SARS- CoV-2 virus variants. Using the same benchmark, its efficacy against the Alpha and Delta variants was 87% and 90%, respectively, 21 days after administering the first dose. Pfizer and BioNTech vaccine: Pfizer's BNT162b2 and BioNTech both showed similar efficacy after 21 days. An 83% effectiveness rate was achieved after 21 days against Beta and Gamma variants. Pfizer- BioNTech increased its vaccine's efficacy significantly after a second dose. After the second dose, 98% of the Beta and Gamma variants did not result in hospitalization or death. Following the second dose, it was equally effective against other variants. Most changes to viruses are inconsequential since they mutate constantly. Some are even harmful to the virus. Some even harm the virus. The disease may be contagious with some mutations, but there are also mutations that can make it more dangerous or infectious. These mutations tend to dominate.