Vaccine protection better than infection immunity?: Here's what CDC says
M3 India Newsdesk Aug 21, 2021
The Center for Disease Control and Prevention (CDC) has stated that new research shows immunisation protects against COVID-19 better than infection.
The results come from CDC research that included over 200 previously infected people from Kentucky, USA. The lack of vaccination increased the risk of reinfection with SARS-CoV-2 by 2.34 times. The research included people aged 18 or older with the first case between March and December 2020 who had a second positive test in May or June of this year. They were evaluated for reinfections. Also, included were individuals who were not reinfected throughout that time span.
Findings of the study
- The research included 246 case-patients and 492 control individuals. 20.3 per cent of case-patients were completely vaccinated, compared to 34.3 per cent of control patients, indicating that unvaccinated individuals were more likely to re-infect than fully vaccinated participants (OR, 2.34; 95 per cent CI, 1.58-3.47).
- Participants who received just a partial vaccine had a 1.56-fold increased risk of reinfection (95 per cent CI, 0.81-3.01). All eligible individuals, including those with prior SARS-CoV-2 infection, should be given immunisation to decrease their risk of future infection.
- The research demonstrates that, although previous immunity is beneficial, it is not as effective at avoiding reinfection as vaccine-induced immunity. It is critical to note that this research did not examine whether individuals with the previous infection were protected from severe infection, which very certainly was due to their immunological state.
- Additionally, it is critical to emphasise that incomplete vaccination was statistically equivalent to fully vaccinated individuals among those with previous immunity. This result, in conjunction with others, should prompt guideline makers to consider recommending a single dose of a two-dose vaccination schedule for those with previous illnesses.
Hybrid immunity
In a second study published in JAMA Network Open, Rush University researchers found that only one vaccination dosage significantly increases the number of virus-fighting immune cells in already infected individuals, more than two injections do for those who have never been sick.
Additionally, new research published in Science and Nature demonstrates that combining a previous infection with vaccination strengthens people's protection against a mutating virus. This is referred to as "hybrid immunity" by Shane Crotty of the La Jolla Institute for Immunology in California.
As per the National Institutes of Health, acquired immunity, which occurs after a person recovers from COVID-19, may offer varying degrees of protection against new variations to different individuals (NIH). Dr. Francis Collins, director of the National Institutes of Health, stated that in comparing natural immunity to vaccine-induced immunity, the researchers discovered that antibodies obtained from the vaccination may target variations more effectively.
This may be due to variations in the antibodies generated after vaccination or the fact that a natural infection only introduces the body to the virus present in the respiratory system, while a vaccine is given to the muscle.
What does this imply for India?
Herd immunity is essential for stopping the pandemic, and authorities have cautioned that individuals who refuse to be vaccinated may worsen the situation. Many Indians have yet to get the COVID-19 vaccine, and the third wave is starting to rise in the country. Unvaccinated people represent the greatest risk, a substantial proportion of hospitalisations, and recent research showed that vaccinations offer better protection against variations than natural immunity. This study implies that previously infected in the 2nd wave are still vulnerable to reinfection if not vaccinated.
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Disclaimer- The views and opinions expressed in this article are those of the author's and do not necessarily reflect the official policy or position of M3 India.
The author is a practising super specialist from New Delhi.
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