Hello,
This blog is about the two articles that I read about the development of the Sars-Cov-2 (Covid-19) vaccine.
The first article I read was from Florian Kramme published by the organization NATURE where the writer talked about how developments of vaccine for covid 19 was possible, the techniques they used, and the risks that are involved in this. This is an interesting article that reviews the different types of vaccines available, how they are made, and the recent outcomes of these vaccines. As traditional vaccines take approximately more than 15 years, SARS-CoV-2 vaccines have been developed in an accelerated manner which only took months to start its first trials. But it is however not clear how long or how much effective these vaccines be. Some vaccine platforms discussed in this article are the inactivated vaccines, live attenuated vaccines, recombinant protein vaccines, replication-incompetent & competent vectors, inactivated vectors, DNA vaccines, and RNA vaccines. The most interesting part of the information that I liked and didn't know before, presented in this article are the systemic and mucosal immune responses to the natural infection with respiratory viruses and vaccination. That is, the natural infection induces mucosal antibody responses (IgA) as well as systemic antibody responses (IgG). The upper tract of the respiratory system is protected by the secretory IgA and the lower respiratory tract is mainly protected by the secretory IgG. It is mainly the intramuscularly or the intradermal vaccinations that are administered to the people which is mainly focusing on the lower respiratory tract that induce IgG and not IgA. There are only a few people who got administered the intranasal vaccination which is mostly for the upper respiratory tract that is protected by the IgA. Therefore, it is possible that the vaccines administered are the disease-preventing or the disease-attenuating immunity and not necessarily sterilizing immunity. I didn't know that there are vaccines that are administered through the nose (even the vaccines for Covid-19). This article also talks about various vaccines available at the market such as the CoronaVac from the Sinovac, Sinopharm, CanSino, AstraZeneca, Moderna, Pfizer, and Novavax.
This is a peer-reviewed article presented by the organization Nature by Florian Klammer published on 23rd September 2020. This article presents the actual results from the clinical trials done with the developed vaccines, some short-term results, and basic information about the development of the vaccines.
The second blog I read titles "Development of an inactivated vaccine Candidate for Sars-CoV-2 " investigated and reported by twenty-five authors was published on 4th November 2020 in an organization called Science. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) belongs to the genus Betacoronavirus (β-CoV) from the family Coronaviridae. "SARS-CoV-2 has a linear, single-stranded, positive-sense RNA genome encoding four structural proteins, with a spike (S), envelope (E), membrane (M), and a nucleocapsid (N)". This article talks about the development of PicoVacc which is a purified inactivated SARS-CoV-2 virus vaccine that is induced with specific neutralizing antibodies of SARS-CoV-2 in mice, rats, and also other non-human primates. This was first tried on monkeys against the SARS-CoV-2 virus which protected them from a rhesus macaque. With the results from this short-term study, the researchers collected multiple SARS-CoV-2 strains from different patients admitted at 11 different hospitals around the world. Then, they chemically inactivated the most armful properties of the virus. The animals were then immunized with one of the two doses they made and inoculated with the SARS-CoV-2 virus. This vaccine seemed to be neutralizing 10 strains of SARS-Cov-2 which gave an idea that it would help protect against other possible strains as well. Three immunizations using two different doses (3 or 6 micrograms per dose) provide partial or complete protection against the SARS-CoV-2 virus according to the clinical tests in the animals. That is, those who received the lowest dose seemed to have a controlled condition of the infection, and those animals who received the highest dose seemed to have more protection and did not see any loads on the pharynx or at the lungs after seven days of the infection. This was also a pretty good article that helped me understand how the clinical trials on animals help determine the possibility to run a clinical run on humans.
Citation of the article:
Krammer, F. SARS-CoV-2 vaccines in development. Nature 586, 516–527 (2020). https://doi.org/10.1038/s41586-020-2798-3
https://www.science.org/doi/full/10.1126/science.abc1932
