Mild side effects more likely with second dose of vaccine, local expert says

Northwestern Medicine infectious disease specialist urges McHenry County residents not to skip their second dose

More than one in four McHenry County residents are fully vaccinated and, as more and more residents go in for their second shot, some of them are reporting mild side effects the second time around that they didn’t experience with their first dose, local vaccine providers said.

The majority of people don’t experience side effects with either dose but, for those who do experience mild illness, it makes sense that it would come with the second dose, said one of Northwestern Medicine’s infectious disease specialists, Dr. Irfan Hafiz.

“That’s normal and expected behavior,” Hafiz said in an interview Wednesday.

“Talking to people who’ve had [COVID-19] before, they say that it’s very similar to what it’s like having [COVID-19], but the difference being when you have [COVID-19], you’re sick and you feel that way for weeks. This is hours instead of weeks that you’re sick,” Hafiz said. “It’s less intense and much shorter in duration.”

The McHenry County Department of Health received a few reports of mild side effects associated with receiving the second dose of the Pfizer and Moderna COVID-19 vaccines, but the county has not seen any serious cases of adverse reactions or anaphylactic responses.

“Subjectively, we are hearing from a very small number of people reports of mild side effects that include malaise [a general feeling of discomfort or illness], headache, and chills that last for about 24 to 48 hours,” Public Health Nursing Director Susan Karras said in an emailed statement Wednesday.

Vaccine recipients are encouraged to stay well-hydrated, rest and to take acetaminophen or ibuprofen as needed if they have a headache, Karras said.

“Just rest. It will pass,” Hafiz said. “Just be patient.”

If symptoms worsen or last beyond 48 hours, both Hafiz and the health department advised that recipients consult with their primary care provider.

The two-shot vaccines currently available in the U.S. – Moderna and Pfizer – use messenger RNA to introduce a piece of the spike proteins on the surface of the coronavirus that causes COVID-19, Hafiz said.

The first time your body is introduced to these proteins is sort of like going to the gym for the first time, Hafiz said. You wander around checking things out, try out a few machines and maybe you pick up a weight or two, but you spend most of your time getting the lay of the land.

The second shot of COVID-19 vaccine, however, is like working out after a few weeks of going to the gym consistently – you know your way around and you get straight to business with a robust workout, he said.

Since you were prepared to work out more effectively the second time around, you’re probably going to be sorer, as is the case for some when it comes to the second shot of the vaccine, Hafiz said.

“But that’s not a bad thing because it means you’re getting better results too,” he said.

This is not to say, however, that if you don’t experience side effects with the vaccine that it is not working, Hafiz said. Experiences vary and, again, people who do feel ill for a short period of time after their second dose are still in the minority.

“Most of the people we talked to say it’s about 24 hours, almost like clockwork, and the symptoms seem to go away,” he said.

People have expressed feeling achey or dehydrated for longer than this, but side effects seem to subside completely by the 48-hour mark, he said.

Hafiz recommended that people plan out their first and second dose so that they don’t coincide with any vacations, major life events or other appointments they are unable to cancel.

Anyone feeling ill after their second shot is also encouraged to report their side effects to V-Safe, an online database used by the Centers for Disease Control and Prevention for tracking and data collection, Karras said. This information on how to enroll and report into V-Safe is posted in the observation areas of all of the health department’s vaccine clinics, but instructions also can be found online.

These side effects should not sway people from following through with getting their second shot, Hafiz said.

“It is really important to get that second dose to give you the full immunity,” Hafiz said. “Do not skip it.”

Northwestern Medicine has been providing COVID-19 vaccines to patients on a limited basis, with the bulk of vaccinations flowing through the McHenry County health department, a spokeswoman for Northwestern Medicine said Wednesday.

They have not had any issues with patients receiving their first dose but not coming back for their second, spokeswoman Michelle Green said.

Vaccinations at clinics run by the McHenry County health department currently are available by appointment only, but a spokeswoman for the department said Thursday that “plans to accept walk-ins are underway” and that an “announcement will be coming soon.”

Kelli Duncan

Kelli Duncan is a reporter for the Northwest Herald covering county government as well as the communities of Huntley, Lake in the Hills, Marengo and Harvard. She has previously covered local politics, immigration and feature stories.