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3 Potential Health Complications Of Injections

Voices against vaccinations grew severalfold at the height of the COVID-19 pandemic, with the first vaccines being approved for emergency use. Despite science proving vaccines’ efficacy and safety time and again, some people reject such notions for reasons that range from half-truths to outright figments of imagination.

One such reason, according to the World Health Organization (WHO), is the belief that vaccines cause adverse side effects. The WHO and other health institutions don’t discount the possibility of getting a sore arm after a shot or worse. It’s uncertain how much risk they pose to the human body, but the likelihood of experiencing severe side effects is rare.

Nevertheless, given that vaccines are lifesaving inventions, people deserve to know what doctors and healthcare professionals administer to their patients. Such information can help them make more informed health decisions. Below are several possible health complications according to current medical research.

  • Shoulder Injury Related To Vaccine Administration (SIRVA)

Healthcare workers are trained to deliver injections to specific sites in the human body. They identify the location around the shoulder by feeling the acromion process, a bone near the scapula, and measuring two to three finger widths down. Then, they imagine a triangle in the area below the fingers, with the ideal injection site at the heart of it.

Unfortunately, there are cases of injections being delivered straight into the acromion itself. This often-underreported mistake leads to SIRVA, inflicting severe pain and affecting the shoulder’s mobility. Sometimes, SIRVA can also stem from using the wrong needle; too-short needles risk more intense pain, while too-long needles can hit a bone or nerve.

While any vaccine delivered via syringe can cause SIRVA, experts say it’s most common among hepatitis, flu, and varicella (chickenpox) vaccines. Because such cases are rare, there aren’t many extensive studies on the condition. If you experience SIRVA, know that the federal government compensates SIRVA patients, so it’s best to consult a professional on what to do after SIRVA diagnosis.

  • Various Neurological Complications

A study published in the Handbook of Clinical Neurology assessed 9.5 million cases logged into the Vaccine Adverse Event Reporting System (VAERS) and found a variety of neurological complications triggered by bacterial and viral vaccines. Some of the most prevalent include:

  • Encephalitis
  • Meningitis
  • Cerebellar ataxia
  • Guillain-Barre syndrome
  • Acute disseminated encephalomyelitis
  • Seizures

The study was published years before the pandemic, but more recent cases have demonstrated that it’s still the case post-pandemic, at least for encephalitis. A systematic review of 65 case studies discovered that autoimmune encephalitis occurred in two out of three cases on the first COVID shot. Most of these cases received either the AstraZeneca or Pfizer vaccine.

However, the authors admitted that 65 cases are too few to be statistically significant and are still unsure how vaccine-induced autoimmune diseases work. Additionally, encephalitis and its many forms comprise a tiny fraction of the VAERS database, alluding to its rarity. As with SIRVA, the federal government also compensates those who suffer from such complications.

  • Hypersensitivity/Allergic Reactions

Patients with known allergies can get them from the components in the vaccine, though scientists suggest they’re much rarer than the previous two, if any. Some of the relevant research made in the past turned out inconclusive, and a Swedish study published in the Lancet proved that there’s no link between vaccines and worsening allergies.

Despite these findings, healthcare professionals didn’t take any chances. During the first wave of COVID inoculations, they asked inoculated patients to wait 15 to 30 minutes before leaving the vaccination site to ensure their allergies don’t flare up. These patients weren’t advised to receive a follow-up dose of the same vaccine if allergic reactions occurred past the observation period. 

The Institute for Vaccine Safety, an organization under the John Hopkins Bloomberg School of Public Health, has outlined dozens of allergens used as ingredients in vaccines, such as:

  • Bovine/calf serum albumin
  • Egg albumin
  • Gelatin
  • Latex
  • Neomycin
  • Thimerosal
  • Yeast

Consulting a doctor before receiving a vaccine is a good idea. Fortunately, with technologies like telehealth being fielded more since the pandemic, getting a doctor’s insight is easier than before and can be done almost anytime, anywhere. 


No medicine is without side effects, at least for the time being. Some drugs have reportedly come close to such an achievement, but these affect the human body differently. Vaccines, COVID or otherwise, are no exception.

Nevertheless, the efficacy and safety of vaccines remain in their favor. Most people can handle them without experiencing severe complications. In the few cases where adverse reactions occur, they’re usually treatable with modern medicine. Therefore, it’s essential to get your shots regularly, as vaccines remain safe and highly effective.