Covid reinfections explained
16 December 2021 | Ministries
Reinfection is defined as an infection in the same individual across a different time period with evidence of two different viral strains within more than 45 days in highly suspicious cases of Covid-19 or more than 90 days in asymptomatic cases with low suspicion. In general, reinfection means a person was infected (got sick) once, recovered, and then later became infected again.
Studies also define reinfection as two positive results with a negative test result in between.
Evidence suggests that 95% of people produce antibodies two weeks after Covid-19 onset.
The minister of Health and Social Services Kalumbi Shangula explained that it is possible that these antibodies could fade over time making a person susceptible again to Covid-19 infection. “Some people may just not develop a fool-proof antibody response in the first place. Therefore, it is possible for a person who have fully recovered from Covid-19 to be reinfected.”
Shangula said that the development of several Covid-19 vaccines has however given hope of a release from the pandemic. "None of the vaccines is 100% effective at stopping transmission or infection. There is always a small risk that some fully vaccinated people will get infected. This is known as “breakthrough infection” and is entirely expected to happen.”
The minister also pointed out that vaccines have limitations. “No vaccine offers full protection to everyone who receive it. This happens because different arms of the immune response produce different defences, namely antibodies that lock onto viruses and neutralising them and the T cells that find and destroy the infected cells. The T cells are important for limiting the severity of illness. We are observing the breakthrough infection and the mild nature of their illnesses. The reasons for breakthrough infection are two-fold.”
The human immune response is encoded in deoxyribonucleic acid (DNA) and varies from person to person. “This variability helps us to respond to an array of germs. It could also be due to other things like poor health, medication or age. On the other hand, the ageing immune system does not respond to new foreign substances that causes the immune system to produce antibodies against it (antigen) neutralising antibodies at all after both doses of vaccines,” the minister said.
According to Shangula another reason for breakthrough infections is due to viral variants that escape immune detection and flourish even in vaccinated people. “A virus is expected to mutate and give raise to variants that may be easily transmitted. The mutations could alter the parts of the virus that recognised by antibodies and T cells.”
The minister reiterated that vaccines are not a cure. “It takes a minimum of two week after vaccination for the immune response to develop. One may get infected within two weeks of vaccination or as a result of breakthrough infections. Getting vaccinated could save your life.”
The minister also emphasised that Covid-19 vaccines provide strong protection against serious illness, hospitalisation and death.
“Being vaccinated makes it less likely that you will pass the virus on to others, thereby protecting those around you. Even after getting vaccinated, keep taking precautions to protect yourself, family, friends and anyone else you may come into contact with.”