A new study conducted by Public Health England (PHE) says that people infected with COVID-19 in the past are likely to be protected against reinfection for several months, supporting similar findings surrounding immunity from this disease.
Even so, experts have warned that even people with immunity may still be able to carry the virus in their nose and throat and therefore have a risk of transmitting it to others. Therefore, it is important that individuals who have acquired the disease and recovered from it continue to take all precautions such as wearing masks, regularly washing their hands, and maintaining a distance of at least two metres from others
What is this finding based on?
Researchers from PHE have been testing tens of thousands of healthcare workers across the UK since June for COVID-19 infections as well as the presence of antibodies. Between June 18 and November 24, scientists detected 44 potential reinfections (out of which two were probable and 42 were possible reinfections) from a total of 6,614 participants who tested positive for antibodies. According to the study, the two probable cases of reinfections reported having experienced COVID-19 during the first wave of the pandemic but were not tested. These two patients reported having less severe symptoms the second time.
Importantly, none of the 44 potential reinfections were tested using PCR during the first wave, but tested positive for antibodies subsequently.
From this, scientists have concluded that naturally acquired immunity as a result of past infection from the SARS-CoV-2 virus provides 83 per cent protection against reinfection, compared to people who have not had the disease before. This protection appears to last for a period of five months from the time that the person first became sick from COVID-19, scientists have said.
What we know about immunity from COVID-19
The longevity of immunity against a disease varies from disease to disease and one of the factors influencing this is the amount of neutralising antibodies produced by the infected person. For instance, if a person gets infected with measles, the immunity typically lasts forever. But in case of the flu, people need to get vaccinated every year to remain protected.
This week, another study published in the journal Science, which is based on the analysis of blood samples from 188 patients said that the body’s immune response to COVID-19 could last for eight months after the onset of symptoms from the initial infection.
The duration of immunity to Covid-19 has been a subject of research through the pandemic, and studies so far have provided various results. In July last year, a study conducted by researchers from King’s College London suggested that immunity might be lost in months.
In November 2020, a study in Pune revealed that nearly 85 per cent of the people who were infected with the virus had developed neutralising antibodies in response to the disease.
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