Expect More Side Effects After Second COVID-19 Vaccine Dose

As the COVID-19 vaccine continues to be rolled out and administered, complaints and questions about its side effects, especially after the second dose, have also increased. Health experts have assured, however, that this is a "normal immune response."

Dr. Kavita Patel said that there's no reason to panic, explaining that the flu-like symptoms that about a third of the people who got their shots experienced are an expected immune response, Today.com reported.

"The second vaccine (dose) — think of it as having that hit to your immune system, and your immune system now recognizes the vaccine, so it does its job," she explained.

The NBC News medical contributor shared that she also experienced symptoms after receiving her second dose, revealing that she "felt, for about 36 hours, like I had the flu."

Explaining the "side effects" of the second COVID-19 vaccine jab, a pediatrician and professor of infectious disease epidemiology at the Johns Hopkins Bloomberg School of Public Health in Baltimore said that the second injection is meant to act as a "booster dose."

"The immune system is seeing the vaccine for the first time with the first dose and is reacting to that, and the cells of the immune system are recruited to kind of recognize that spike protein (the part of the coronavirus that the vaccine affects). So when the body's immune system sees (the vaccine) a second time, there are more cells and there's a more intense immune response, resulting in those side effects," Dr. Bill Moss said.

Reports of severe side effects from the coronavirus vaccine remain "anecdotal," according to Andrew Heinrich of the Yale School of Public Health in New Haven, Connecticut, noting that there is nothing "statistically valid about that trend."

According to health experts, the symptoms one might experience upon getting vaccinated may include but are not limited to the following:

• Localized reactions (swelling, rash, or soreness at the injection site)
• Fatigue
• Chills
• Fever
• Headache

The Centers for Disease Control and Prevention (CDC) has advised seeing a doctor if the symptoms are still there after 24 hours.

Patel suggested that people should be "prepared" for either possibility. "If you don't have a reaction, you don't need to worry that it didn't work. Every human and body is different," she said.