Recently the world reached a milestone of one year since COVID-19 vaccines were first authorized by the FDA and other regulatory agencies around the world. Vaccine protection against COVID-19 has proven to be extremely effective, especially against severe disease, hospitalization and death. Having the virus offers some defense against future illness, but protection after infection is less predictable than protection after vaccination. Protection against COVID-19 from both infection and vaccination wanes over time.
Both booster shots and "hybrid immunity" (a combination of vaccination and infection) significantly increase our bodies' defenses against COVID-19. The increase in protection that hybrid immunity and boosters provide is especially important when you factor in virus variants – such as the highly infectious delta variant and the newly discovered omicron variant that is spreading worldwide. People with immunity that comes only from infection are more susceptible to new variants.
In the case of omicron, much remains to be learned. Scientists have already observed that omicron contains more mutations than other variants of concern, including the delta variant. These mutations may make it easier for the virus to pierce through our immunity shields, whether from vaccination or prior infection. In South Africa, where the variant was first identified, early signs indicate that reinfection rates are higher from omicron than from previous strains of the virus.
"Reinfection, especially very early on, is rare," said Diego Hijano, MD, of St. Jude Infectious Diseases. "But as we have new variants and time lapses after having the infection, it can happen. In addition, there is clear benefit to getting vaccinated, especially as we have new variants emerging in different parts of the world."
Immunity conveyed from vaccination or infection is critical to protecting yourself against severe illness from COVID-19. However, vaccination – including a booster shot – is the most reliable way to ensure protection. When someone recovers from COVID-19, hybrid immunity with all recommended doses of vaccine provides even broader cross-protection against emerging variants.
Both clinical trials and real-world evidence from more than 8.4 billion vaccine doses given worldwide show that side effects from vaccination are generally mild and disappear within two to three days. Severe side effects such as allergic reaction, myocarditis and blood clots are extremely rare.
The outcomes of the disease itself are less easy to predict. Pre-existing conditions such as high blood pressure, diabetes and obesity can complicate the course of COVID-19. When it comes to heart inflammation, research has shown that the risk of myocarditis in people with COVID-19 was 6 – 34 times higher compared to people who received an mRNA vaccine.
Long-term effects
A year after immunization against COVID-19 began, some people are concerned about unknown long-term effects. Decades of research shows that side effects from vaccination generally occur within six weeks. There is no plausible mechanism that allows vaccines or any of their components to cause health problems years after being administered.
“The concept that vaccines have to have years of research comes from the need to vaccinate enough individuals to detect very rare side effects and not because these side effects appear many years after receiving the vaccine,” Hijano said. "In the case of COVID-19 vaccines, with over 8.4 billion doses administered globally and over 484 million in the U.S. alone, no additional rare, unexpected side effects will be observed."
Conversely, prolonged symptoms following COVID-19 infection are well documented and have been shown to disrupt peoples’ lives for months after infection. When a cohort of low-risk health care workers with mild COVID-19 was assessed eight months after infection, one in 10 still had at least one symptom that was disrupting their work, social or home life. While the most common long-term symptoms from the virus are fatigue, respiratory problems, and loss of smell and taste, patients have also experienced persistent shortness of breath or difficulty breathing; chest or joint pain; fast or pounding heartbeat; depression or anxiety; and memory, concentration or sleep problems.
In the U.S., more than 790,000 people have died from COVID-19. Worldwide, that number is more than 5 million. In contrast, five deaths appeared to be linked to thrombosis that occurred after people got the Johnson & Johnson vaccine. We now know how to recognize and treat people who develop these blood clots, which means that future deaths related to this very rare side effect can be prevented. “Statements claiming that deaths after vaccination equal or exceed those caused by the virus are inaccurate, misleading and irresponsible,” Hijano said.
The bottom line: get vaccinated
Medical experts worldwide, including infectious disease physicians at St. Jude, emphasize that the risk of severe illness and death from COVID-19 far outweighs any benefits of immunity from infection.
Whether or not you've been infected with COVID-19, vaccination is your best line of defense against the virus. Vaccines are also the fastest and best way we can protect our St. Jude patients.
"The recommendation continues to be for everyone to get vaccinated, including boosters, even if you had COVID-19," Hijano said.
Read more inspiring stories
-
Thanks to a St. Jude clinical trial, Olivia and her family are living “in the now”
Over a decade of research brings a treatment to the forefront for children with low-grade gliomas. For Olivia Thatcher, that treatment came at the right time.
-
Writing her story helps Indiana teen process her emotions
Through the St. Jude ChronCan study, Jinger Vincent uses creative writing to process her cancer experience.
-
PFCC offers mom a way to help others, give back
Caregiver reflects on giving back to St. Jude
-
Journey to the Jude: Joseph Gutierrez
The Journey to the Jude series highlights how St. Jude employees developed a passion for their careers and how that journey translates to their current roles. Read about Joseph Gutierrez, a pediatric oncology nurse
-
Cultural navigator brings new level of support to international families
Cultural navigation is important in providing exceptional care for international families at St. Jude. Find out how the hospital helps these families.
-
Challenges Can’t Keep Jolly Down
Jolly Green tackles severe aplastic anemia thanks to St. Jude, faith, and family. Read his story.
-
Patient reflects on 60th anniversary as childhood cancer survivor
Patient reflects on her 60th anniversary as a childhood cancer survivor
-
Patient finds support, help and hope for Friedrich’s ataxia
Taylor Hurdle is taking part in a clinical trial for Friedreich’s ataxia at St. Jude Children’s Research Hospital.
-
Finding Hope in Clinical Trials
A medulloblastoma clinical trial offered hope to 7-year-old Kinlee Johnson and her family. Learn more.
-
From Pain Crises to Good Vibes
Rashawn Hendrix says St. Jude doctors take his sickle cell pain seriously and that help him manage.it.
-
Family chooses St. Jude because of SAMD9/SAMD9L researcher
Family chooses St. Jude for care because of its expertise in SAMD9/SAMD9L syndrome.
-
Research may help Camille take her first steps
Research conducted by the Center for Experimental Neurotherapeutics may help patients like Camille, who has type 2 spinal muscular atrophy, gain the ability to walk.
-
Insights Learned Through Cancer Experience Now Help Others
St. Jude survivor Tristan Elsener has survived multiple bouts of cancer. He and his family have gained insights that can help others. Learn about the Caregivers Share podcast.
-
Molecular diagnostics give Fletcher what some thought impossible: a diagnosis and treatment plan
Molecular diagnostics give Fletcher Fazenbaker what some thought impossible: a diagnosis and treatment plan for infant-type hemispheric glioma (IHG), a subtype of high-grade glioma — a rare brain tumor — that was not classified by the World Health Organization’s brain tumor classification guide until 2021
-
Surviving childhood cancer is just the beginning of Darshana’s story
Darshana Magan survived cancer 30 years ago, but her treatment caused long-term health issues. Read how she cares for her health and encourages other survivors.
Careers
At St. Jude, your career makes a difference. We offer outstanding opportunities in the basic and translational sciences, clinical research, patient care and many other areas for talented individuals.