Getting to know Covid-19 vaccines – The Manila Times

First of 2 parts
Covid-19 vaccines have one goal: to fight and beat the disease and, thereby, put an end to the pandemic. But they go to war armed with a variety of weapons, approaches and genetic makeup. This nonuniformity, along with uneven degrees of success they offer, not to mention their cost that varies according to complexity of technology used to mass-produce them, add to the hesitation that has crept into the public mind. This explains why the government, in the exercise of its power and use of available resources, must exploit leadership and moral suasion to rally public support behind its multibillion-peso vaccination program.

These vaccines work differently for different people. Government must lead in choosing which vaccine should work best for the people. People will be better served if the government can make available for them a complete menu or portfolio of safe and effective vaccines. Equally important is providing people access to information that will help them make appropriate choices.

As of Jan. 18, 2021, at least nine vaccines have been approved or authorized for public use by globally recognized regulatory agencies. Vaccine tracker identifies the approved vaccines as follows: Comirnaty by Pfizer/BioNTech/Fosun Pharma, Moderna, CoronaVac by Sinovac, AstraZeneca by Barda/Oxford, Sinopharm, Sputnik V by Gamaleya Institute, EpiVacCorona, Covaxin, and Janssen by Johnson & Johnson.

Novavax, Aivita Biomedical and Universitätsklinikum Hamburg-Eppendorf lead at least 59 other vaccines at various stages of clinical trials.

Table 1 summarizes the technical descriptions of the nine approved and one pending vaccines.

At the individual level, which of the available vaccines one should get may well depend on several factors such as age and existing health condition. At the national level, procurement decisions can be guided by cost, efficacy rates, availability, as well as logistics (like storage and handling) requirements.

Approved vaccines fall under two broad types or categories, namely: classical vaccines and next-generation vaccines.

Classical vaccines include live (weakened) virus vaccines, inactivated virus vaccines, and protein-based sub-unit vaccines. Both weakened, or attenuated, and inactivated vaccines are also called whole virus vaccines. Next-generation vaccine include nucleic acid-based vaccines (such as those based on mRNA) and viral vector vaccines.

How they work

From experts, we know that vaccines “leverage the natural powers of the body’s immune system. The immune system is a complex array of cells and systems that work to identify and eliminate infectious organisms [such as viruses] in the body.”

The US Centers for Disease Control and Prevention puts it in plain language:

“Covid-19 vaccines help our bodies develop immunity to the virus that causes Covid-19 without us having to get the illness. Different types of vaccines work in different ways to offer protection, but with all types of vaccines, the body is left with a supply of ‘memory’ T-lymphocytes as well as B-lymphocytes that will remember how to fight that virus in the future.

“It typically takes a few weeks for the body to produce T-lymphocytes and B-lymphocytes after vaccination. Therefore, it is possible that a person could be infected with the virus that causes Covid-19 just before or just after vaccination and then get sick because the vaccine did not have enough time to provide protection.

“Sometimes after vaccination, the process of building immunity can cause symptoms, such as fever. These symptoms are normal and are a sign that the body is building immunity.”

To be continued


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