How does the second COVID-19 vaccine dose work on the human body

Gulf Today, Staff Reporter

The UAE Ministry of Health and Prevention (Mohap) has highlighted the importance of second dose of the COVID-19 vaccine.

The ministry said that the vaccine prepares the body to fight the infection caused by viruses or bacteria.

The vaccine contains inactivated or weakened particles of the virus that causes the disease, or contains the genetic code works to provoke an immune response.

This helps the body to recognise foreign invaders and produce antibodies to fight them.

The health authorities said, “Adhering to all the vaccine doses and to all recommended precautionary measures, such as wearing a mask, social distancing and washing hands, would stop the spread of COVID-19 virus in the society.”

The authorities said most vaccines need a second dose to provide adequate protection.

The vaccine activates two types of cells, but they are short-lived.

The second dose is a tool to expose the body again to antigens (molecules) that exist in the disease and triggers immune response when receiving the second dose, antibodies appear again in the body in larger numbers.

The ministry also spoke about the herd immunity.

It said herd immunity is a form of indirect protection from infectious disease.

Herd immunity occurs when a sufficient percentage of a population has become immune to an infection, whether through vaccination or previous infections.

The ministry said coordination is ongoing with the involved health bodies to determine the frequency of this vaccine, alike to other vaccines such as the seasonal flu, to ensuring providing adequate protection to individuals.

For those, who had to be admitted to a hospital for COVID-19 or had moderate-to-severe COVID-19 infection must seek the opinion of their medical team with regard if they should take the second dose of the vaccine.

How does different vaccines work?

The Sinopharm vaccine works using dead viral particles to expose the body's immune system to the virus without risking a reaction. The vaccine stimulates the human immune system and forms antibodies to resist the COVID-19 virus.

Authorities said that Pfizer-Bionic vaccine works with RNA technology.

This means that part of the gene code is injected into the body, prompting it to start producing s-protein on the shell of the virus that triggers immune response.

Both AstraZeneca and Sputnik V vaccine are based on a viral vector, it is placed on another virus called adenovirus, which is modified and molecules of the emerging #Covid19 virus are added to it. The virus is considered weak but sufficient to produce antibodies.

The UAE Health sector said, “Many people focus on differences in vaccines and how they are manufactured and preserved, but despite these differences, vaccines are similar in stimulating the body by producing antibodies, giving the necessary immunity in the event of exposure to the virus.” Sinopharm’s clinical trials have shown that its vaccine can reduce the chances of contracting COVID-19 and prevent complications from the disease, but no one can yet determine how long protection will last.

Meaning that these cells can remember the pathogen, if the infection is encountered again, and stimulate the immune system to reproduce antibodies that are resistant to the virus.

This applies to all vaccines developed to treat COVID-19.

The level of antibodies can decrease over months, but the immune system also contains special cells called "memory cells" that may retain COVID-19 information for long periods of time that may reach years.

Researchers found that these cells underwent cycles of mutations even after recovery and were able to produce effective antibodies more than those initially caused by the infection. Tests have also indicated that these antibodies are able to identify mutated strains.