COVID-19 Vaccine’s Second Dose May Trigger Additional Side Effects

by DailyHealthPost Editorial

Several mass-produced Covid-19 vaccines may come with unwanted side effects. Given the short time they had to be developed, it was inevitable. In the case of the Pfizer-BioNTech vaccine, the side effects include nausea, pain at the injection site, muscle pain, headache, knee pain, and fever. 3.8% of the clinical trial participants also reported exhaustion while 9.7% of the Moderna vaccine patients experienced fatigue and another 4.5% got headaches. 

Is the second vaccine shot more likely to cause side effects?

Recent anecdotal reports have led some to speculate that the second shot of most Covid-19 vaccines may bring an increased risk of side effects. One such case was brought up by David Flores, a nurse working in the University of California San Diego health center’s emergency room.

Mr. Flores got the second shot of his Pfizer-BioNTech vaccine on January 7 and reported strong joint pains in his ankles, knees, hips, and back. He said that his hips “were killing” him and that he had a hard time sleeping the night after the vaccination. According to Flores, other patients have also reported experiencing additional side effects after the second shot compared to the first one.


And while this is purely anecdotal, it merits further investigation. Dr. Edward Cachay, a UCSD infectious disease expert, notes that the second booster shot of the vaccine is necessary if we want the vaccine to be effective. He notes that the first shot has only a 51% chance to be effective while the second shot brings that up to 95%. The whole process also takes 10 to 14 days after the second dose to result in effective protection against the virus.

So, even if side-effects prove to be more likely after the second dose, the trade-off is still worth it, considering that the side-effects wear off after a day or two.

David Flores also agrees with that, confirming that he’s happy he took the second shot on January 7.

USCD officials have so far given Covid-19 vaccines to nearly 10,000 team members and are continuing with their vaccination efforts despite ~75% of team members still refusing to take the vaccine.

Joe Biden receives second dose of Pfizer Covid-19 vaccine