Since the early days of the pandemic, significant attention is centered on COVID-19 vaccine development. It is assumed that it will suppress the virus and provide relaxation from economically challenging and other brutal control measures. With a lot at stake, it is not surprising that COVID-19 vaccines have become both a public and political obsession. In such a scenario, researchers must ensure that they don’t develop a vaccine in haste to prove their research proficiencies.

Vaccine development is typically a long game. It is evident from the report that stated the U.S. Food and Drug Administration’s (FDA) approval for the first vaccine against the Ebola virus last year, after years of infection. On average, it takes around 10 years to develop a vaccine. With the COVID-19 crisis on the horizon, everyone is hoping that this time will be different.

Currently, ten vaccines against severe acute respiratory syndrome coronavirus 2 (SARS-COV-2) are under clinical trials. According to Chairman and Chief Executive at Pfizer, Albert Bourla, their vaccine candidate performed much better than the expert’s expectations. Its production has also begun, and it is estimated that it will supply 50 million doses in 2020 and 1.3 billion quantities by 2021. The U.K. has placed an order and is hopeful for receiving 10 million doses by the end of 2020, additional 30 million doses next year.
After the vaccine enters the market, its administration to the masses will depend upon the infection’s adversity. The worse hit regions and communities will be prioritized for receiving the vaccine dose. After administration, the vaccine’s efficiency will be studied among various groups.

Key Mechanism of Action Behind the Vaccines

Many glycosylated S proteins are present on the surface of the SARS-CoV2 virus. These epitopes bind to the host cell receptor angiotensin-converting enzyme 2 (ACE2), mediating viral cell entry. When the S protein binds to the receptor, T.M. protease serine 2 (TMPRSS2), a type 2 T.M. serine protease located on the host cell membrane, promotes virus entry cells activating the S protein. Once the virus enters the cell, the viral RNA is released, polyproteins are translated from the RNA genome, and replication and transcription of the viral RNA genome occur via protein cleavage and subsequent assembly of the replicase–transcriptase complex. Viral RNA is replicated, and structural proteins are synthesized, assembled, and packaged in the host cell, after which viral particles are released.

The S protein on the virus’s surface is a crucial factor responsible for the infection. It is a trimeric class I TM glycoprotein responsible for viral entry, and it is present in all kinds of HCoVs, as well as in other viruses such as HIV (HIV glycoprotein 160, Env), influenza virus (influenza hemagglutinin, H.A.), paramyxovirus (paramyxovirus F), and Ebola (Ebola virus glycoprotein). Like other Coronaviruses, the S protein of SARS-CoV-2 mediates receptor recognition, cell attachment, and fusion during viral infection.

Currently, no specific therapeutic or prophylactic measure has been employed clinically to treat or prevent SARS-CoV-2 infection. Non-specific antiviral drugs, such as IFN-α (recombinant human IFN-α1b, IFN-α2a), Remdesivir, Chloroquine, Favipiravir, and Lopinavir–ritonavir (Aluvia), have been clinically used to treat COVID-19. Nevertheless, NIAID-VRC scientists are utilizing a candidate vaccine expressing SARS-CoV-2 S protein in mRNA vaccine platform technology. Continued strengthening of the SARS-CoV-2 S protein monitoring is of great significance for subsequent new drug development and protection against COVID-19.

Covid Vaccine Tracker: When will a coronavirus vaccine be ready?

More than 150 teams of researchers are racing to develop a safe and effective vaccine, out of which around twelve have reached phase 3 of clinical trials and 6 six have been approved for limited use. The government has approved these six vaccine candidates of China and Russia without waiting for phase 3 trials.

Recent Vaccine News

• Before US-FDA, Britain can give grant approval for emergency use to Pfizer-BioNTech COVID-19 vaccine this week.

• On Friday, US-FDA mentioned holding a meeting on December 10th to decide on Pfizer’s Vaccine’s authorization.

• Pfizer and BioNTech announced that their mRNA vaccine was found to prevent 95% of clinical trial infections. They later added that the vaccine had displayed much better effectiveness than the experts speculated. “The first interim analysis of our global Phase 3 study provides evidence that a vaccine may effectively prevent COVID-19. It is a victory for innovation, science and a global collaborative effort.” “When we embarked on this journey 10 months ago, this is what we aspired to achieve. Especially today, we are all in the midst of a second wave and many of us in lockdown. We appreciate even more how important this milestone is on our path towards ending this pandemic and for all of us to regain a sense of normality. We will continue to collect further data as the trial continues to enroll for a final analysis planned when a total of 164 confirmed COVID-19 cases have accrued. I want to thank everyone who has contributed to making this important achievement possible,” said Prof. Ugur Sahin, BioNTech co-founder and CEO.

• Moderna stated that its COVID-19 vaccine candidate had shown 94.5% efficacy in preliminary analysis of large-scale phase 3 studies. This news came just after a week of positive readouts from BioNTech and Pfizer’s COVID-19 vaccine candidate. Chief Executive at Moderna, Stéphane Bancel, mentioned that the moment was “pivotal” and “has given us the first clinical validation that our vaccine can prevent Covid-19 disease, including severe disease”.

• US-FDA has authorized the emergency use of monoclonal antibodies, casirivimab and imdevimab. These are directed to be administered together to treat mild to moderate COVID-19 in adults and pediatric patients.

It is expected that AstraZeneca and the University of Oxford will also present the results of their vaccine candidate this year and will be approved for emergency use by the end of this year. Still, many questions are raised about the longevity, efficacy, and protection from this novel coronavirus and the ease and effectiveness with which vaccines can be adopted worldwide.