Covid: UAE doctors explain why chances of reinfection are higher with some variants

Medics in the country reiterate the dangers of the strain and how it affects vaccinated people



by

Nandini Sircar

Published: Tue 11 Jan 2022, 5:51 PM

Last updated: Wed 12 Jan 2022, 7:24 AM

The Omicron variant can come with an increased risk of reinfection, even among those who've had Covid-19 earlier, but it usually also comes in a much milder form in immunized communities, say medics.

Thus, doctors in the UAE reiterate the silver lining is that Omicron is not as deadly in vaccinated people despite the breakthrough infections.

Dr Priya Bharat, Specialist Internal Medicine, Prime Medical Center says, "The B.1.1.529 (Omicron) variant has many mutations, some of which are concerning. Preliminary evidence suggests an increased risk of reinfection with this variant, as compared to other variants. Centers for Disease Control and Prevention (CDC) expects that anyone with Omicron infection can spread the virus to others, even if they are vaccinated or don't have symptoms."

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Medics say reinfection can be worrying

Dr Saheer Sainalabdeen, a specialist pulmonologist at Medeor Hospital, Dubai, opines, "Reinfection means getting infected by Covid-19 twice. A study conducted in the UK in December shows that the omicron variant is five times more infectious compared to the Delta variant. So, the possible explanation for reinfection, as of now, is the highly contagious nature of the virus, how much immunity can the vaccines build to resist the virus, and the waning vaccine effect over time."

Sainalabdeen adds, "More than reinfection, the concerning factor is of confection -- the combination of Omicron with another variant. How the body immunity will behave to this can only be understood in the coming days."

Medics say the virus is mutating like the influenza virus, and Omicron is not necessarily different from the other variants.

Dr Sherif Fayed, Consultant Pulmonologist, Al Zahra Hospital says, "In people who previously had Covid 19, we noticed that the reinfection happens to occur in milder form rather than being severe. Generally, we haven't seen anybody who suffered from a severe case as a second infection."

"The vaccination doesn't protect you from catching the reinfection by 100 per cent, but it protects you from the complications and the severity of the infection itself. This means that all of those who got vaccinated, their death rate is minimal compared to those who didn't get vaccinated. Admissions to the ICU are also less compared to those who are not vaccinated."

While the virus presents as an upper respiratory infection commonly lasting about four days, it's said it does not cause pneumonia and respiratory complications as much as delta or the earlier variants in inoculated people.

Omicron has 36 mutations in its spike protein

Dr Shyam Raja Mohan, specialist internal medicine, Prime Hospital, explains exactly why Omicron has more chances of reinfection and can escape vaccination immunity.

He says, "There are about 50 mutations in the omicron variant compared to the original Covid-19 virus isolated in China in 2019. One of the most important areas on the Covid virus is the spike protein. This is the part of the virus that comes into contact with human cells, and is a prominent target for the immune system. Antibodies attach to the spike protein and stop the virus from causing an infection. This makes the spike protein critical for how the virus functions and for how the immune system stops it."

"Omicron has 36 mutations in its spike protein, compared to 10 in alpha, 12 in gamma, and nine in delta. Within its spike protein, Omicron has mutations in the part of the spike that connects directly to a receptor called ACE2 on human cells. Omicron's mutations seem to increase its affinity for ACE2, allowing it to infect cells more efficiently, thereby increasing its reproduction rate and transmissibility."

"There are mutations on other parts of Omicron's spike protein as well. Due to these changes, antibodies have a harder time recognizing and sticking to Omicron's spike. That may explain why Omicron seems to cause more reinfections and breakthrough infections in vaccinated people compared to other variants", adds Mohan.


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