All you need to know about COVID-19 re-infection
Since the onset of Omicron infection, COVID symptoms have taken a milder turn. As per experts, the heavily mutated variant of concern causes less severe ailments as compared to the Delta, leading to cold-like symptoms such as a sore throat, runny nose, fatigue and back pain. In certain cases, people have reported gastrointestinal symptoms such as nausea, vomiting and loss of appetite.
Additionally, experts have also warned against possible COVID re-infection, which was hardly the case with previous COVID variants.
Also read: Coronavirus: Why you shouldn’t feel ‘invincible’ if you have had COVID
What is COVID reinfection?
Reinfection is when a person gets infected with a disease, recovers over time, but develops the same illness again.
According to the Centers for Disease Control and Prevention (CDC), "Reinfection with the virus that causes COVID-19 means a person was infected, recovered, and then later became infected again. After recovering from COVID-19, most individuals will have some protection from repeat infections." However, as per the US health agency, reinfections do occur after COVID-19, but more research is awaited.
How prevalent are re-infection cases, especially with the Omicron variant in circulation?
Previously, the World Health Organization (WHO) said, "Preliminary evidence suggests there may be an increased risk of reinfection with Omicron (ie, people who have previously had COVID-19 could become reinfected more easily with Omicron), as compared to other variants of concern, but information is limited."
Health experts in India have also not ruled out the possibility of re-infection especially with the highly transmissible variant, Omicron, in circulation.
Earlier, Maharashtra COVID task force member Dr Shashank Joshi told TOI, "Reinfection is something that we cannot ignore in COVID at all, irrespective of the variant. Even if people have recently recovered from an Omicron infection, they cannot take the risk of improper masking or no masking, because reinfection with the variant has still not been ruled out."
Another member of the task force, Dr Rahul Pandit added by saying, "There is still no official Omicron reinfection case reported anywhere in India. But not following COVID-appropriate behaviour after recent COVID recovery is still not an option because one never knows what variant may surface in the future.
He further advised people to mask up, maintain physical distancing in order to avoid a possible reinfection from any variant.
See more: Coronavirus symptoms: Pain in these two places could be sign of an Omicron infection
Are symptoms from re-infection less severe?
As is known, fully vaccinated individuals are well protected against severe COVID-19 infections as opposed to their unvaccinated counterparts. Similarly, experts believe people who have had COVID-19 once can expect to experience a milder and a less severe re-infection. This is because, it is believed that the re-infected person is likely to have some pre-existing immunity from their primary infection. Additionally, since many have already received both their doses of COVID vaccines - some have even got their boosters - they're likely to have higher levels of immunity.
However, experts believe much depends on which variant you get infected with.
As per UK’s Office for National Statistics (ONS) report, reinfections with alpha gave people symptoms only 20 percent of the time, while delta reinfections caused symptoms in 44 percent of the cases and omicron in 46 percent. People reinfected with alpha were less likely to develop symptoms the second time as compared to their primary infection. Delta reinfection was more likely to induce symptoms the second time. However, when it comes to Omicron, the rate of symptoms was almost the same for reinfection and primary infection.
Why are repeated COVID infections a possibility?
Research in the past has claimed that immunity from a natural infection may last for over 6 months or more. Another study conducted by a team of researchers at the University College London (UCL) suggested that prior COVID infection can reduce the risk of developing the disease for upto 10 months after infection.
Although one cannot say for certain whether a COVID-19 reinfection can occur, waning immunity is a subject scientists and doctors have been discussing since the beginning of the pandemic.
Scientists believe immunity produced from an infection wanes over a certain period of time, which is the same for vaccine-induced immunity. This is why the demands for vaccine boosters have increased in recent times, since it helps re-expose the body's immune system to the viral particle and triggers immune responses.
Do COVID re-infection help build immunity against the virus?
Most possibly yes!
The human body has two main lines of defense i.e. the innate immune system and the adaptive immune system.
An innate immune response kicks in early when a viral particle is identified. This goes on to trigger a host cell to release a protein that hinders the virus's replication, or it can involve the immune system to try and eliminate the compromised cells.
On the other hand, an adaptive immune response takes more time to trigger a response, because the immune system has to first recognize the viral invader before initiating a specialized attack.
Antibodies are part of the adaptive immune system. Once a virus has been detected and identified, the B cells make antibodies that can attach itself onto the viruses and block them from getting into cells. Your body's immune system is therefore able to remember the virus for a long time, which in turn avoids repeated infections.
That said, any form of COVID-19 infection, even if it is a repeated infection, can help build and strengthen immunity, since it re-exposes the immune system to the viral pathogen and produces antibodies.