Understanding COVID vaccine side affects

Since the beginning of the COVID-19 pandemic, Dr. Hai Shao, a board certified infectious disease specialist, has been involved in all aspects of the management of COVID-19. Shao practices at both Sharp Chula Vista Medical Center and Scripps Mer­cy Hospital Chula Vista. He is the medical director for both hospitals in infection control and hospital epidemiology and the Antibiotic Stewardship Pro­gram. He said his work has ranged from infection control, PPE, treatment, diagnosis, testing and vac­cinations. Shao sits on multi committees laying out and implementing polices. Shao said it is extremely important to get vaccinated as COVID-19 is an ex­tremely serious illness.

“Many people thought this was just another form of an influenza and I would beg to differ on my own clinical experience and knowledge about this virus,” said Shao. “This virus kills people 10 times higher than influenza. I have been through so many flu seasons in hospital ICUs seeing people struggle, but I have never, ever in my career seen such a bad virus causing so much death and comorbidities in my live.”

Shao said people should not be complacent, get vaccinated with herd immunity being the ultimate goal.

“As more people get vaccinated and protected, the more difficult it is for the virus to spread and trans­mit within a community and making people sick,” he said. “We can save a tremendous number of re­sources in our healthcare industry and obviously, improve the quality of life for everyone that do not have to be home sheltered and businesses closed.”

Both the Pfizer and Moderna vaccines are ex­tremely safe and highly effective on all the data collected so far, said Shao. Both vaccines use the messenger RNA that introduces messenger technol­ogy so the body will automatically make a protein from the template. He said this protein develops to a part of the viral particle that the immune systems recognizes that it is a foreign protein and develops antibodies and immune responses.

Shao said symptoms that people experience after the inoculations can all be found at the Center for Disease Control and Prevention website v-safe page. This is a project that the CDC put out to encourage people to use their smartphone to tell CDC about any side effects that they experience getting the COVID-19 vaccines. By Jan. 27, when it published the initial safety data, more than 22 million people had gotten either the Pfizer or Moderna vaccine and reported their symptoms. Visit www.cdc.gov/coronavirus/2019-ncov/vaccines/safety/vsafe.

Shao said if you look at symptoms from people that received their second shot, there is a significant difference from the first dose.

“Usually, the symptoms are very mild with both vaccines with the first shot,” said Shao. “Largely muscle aches from the injection site for about 24 hours that will disappear. People will typically report more symptoms after their second shot. The most common symptom, pain or body aches were report­ed by 70% of people that got the vaccine. Fatigue is at about 33%, headache 29%, muscle ache 23%, chills and/or fever 11% and joint pains at about 10%.”

Shao said the good news is symptoms after the vaccinations are seldomly related to the respirator track and secondly, the symptoms are short lived.

“Usually less than 24-48 hours and can be relieved by over the counter medications such as Tylenol or ibuprofen. Most people tolerate both shots very well,” he said.

Shao said there is a rare incidence of anaphy­lactic shock among people that were vaccinated. For Pfizer, only five out of one million people ex­perienced this, usually women which had a history of anaphylactic reactions before. For Moderna, it is lower. It is about 2.8 out of one million people. “The good news is that so far, no one had died from side affects or reactions to either vaccine,” he said. “The vaccines are extremely safe and based on trial data, they are highly effective in preventing infection from COVID-19. Most symptoms are a result of the im­mune system responding.”

Shao said many companies are working on other forms of vac­cinations and their research has come to a point where they have conducted enough research and advocacy and waiting for the FDA to approve. The frontrunners are Johnson & Johnson which uses an adenovirus mechanism, which means you only need one shot.

“The protection is not as high as Pfizer or Moderna, but it is decent, easy to give, easy to manufacture. AstroZeneca was currently approved by the British government,” he said. “So far, the data suggests that they are both very safe and highly effective.”

The CDC reports there are variants of the virus that causes COVID-19 now circulating glob­ally:

The United Kingdom identified a variant with many mutations in the fall of 2020. This variant spreads more easily and quickly than other variants. This variant was first detected in the US at the end of December 2020. In South Africa, another variant emerged independently, originally detect­ed in early October 2020. Cases caused by this variant have been reported in the US at the end of January 2021.The CDC reported in Brazil, a variant emerged in early January. This variant con­tains a set of additional mutations that may affect its ability to be recognized by antibodies. This variant was first detected in the US at the end of January 2021.

“These variants seem to spread more easily and quickly than other variants, which may lead to more cases of COVID-19. An increase in the number of cases will put more strain on health care resources, lead to more hospitalizations, and potentially more deaths. So far, studies sug­gest that antibodies generated through vaccination with current­ly authorized vaccines recognize these variants. CDC reports this is being thoroughly investigated and more studies are underway.”

Understanding COVID vaccine side affects


  1. It should be noted that the vaccines do not appear to stop people from catching covid, nor do they prevent transmission either. Israel, with one of the highest vaccination rates, is currently experiencing its worst ever surge of covid. They even went so far as to tell it’s people that having two injections is no longer considered full vaccination and that they must get another injection to be allowed to travel freely. People should ask themselves at this point how many times they are going to get a booster shot.

    Also interesting is the fact that the San Diego County website currently shows the covid-19 death count for children aged 0-9 as ZERO, while the all-time death count for children age 10-19 is a total of TWO. Children should not changing anything about what they do in their daily lives as they are not susceptible to serious illness according to official statistics.


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