Immunity to COVID-19 in recovered patients may only last a few months, a new study conducted by King’s College London has suggested.
According to the research, which has not yet been peer-reviewed, immunity antibodies decrease significantly in the three months following infection, leaving patients susceptible to reinfection year after year – similar to the common cold.
In what is believed to be the first longitudinal study of its kind, researchers looked into the immune response of 90 patients and healthcare workers at Guy’s and St Thomas’ NHS Trust.
While the analysis revealed a “potent” level of antibodies could be found in 60 per cent of participants while at the peak of their battle with coronavirus, sequential blood tests showed only 17 per cent sustained that same level of potency three months later.
Antibodies decreased 23-fold in some cases, and were depleted entirely in others.
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The report states that its findings have “important implications when considering widespread (antibody) testing, (antibody) protection against re-infection with (COVID-19) and the durability of vaccine protection.”
It added: “Further studies using sequential samples from these individuals is required to fully determine the longevity of the (antibody) response and studies determining the (antibodies’) threshold for protection from re-infection are needed.”
How do viruses make us ill?
Viruses are extremely tiny parasites made of genetic material, wrapped in proteins and sometimes an outer membrane layer, which hijack living cells to reproduce themselves. We’re exposed to viruses every day, but our immune system prevents the vast majority of them from taking hold – especially those that we’ve fought off before, or been vaccinated against.
The first stages of an infection happen when a virus gets past our physical barriers of skin and mucus, and enters a suitable cell. Once inside, a virus can take over the cell, forcing the cell to make many copies of the virus (replicate), which damages the cell and sometimes kills it. The newly-made viruses are released to find a new cell. We get ill when a virus has established an infection in many cells, and our body’s normal functioning changes.
Viruses often infect specific places in our bodies, which is where we feel their effect. Rhinoviruses infect our upper airways behind our nose, and we respond with snot and sneezes: a common cold. The coronavirus that emerged in 2019 (called SARS-CoV-2) infects our lower airways, including our lungs, leading to pneumonia.
Our body fights viruses by creating an inflammatory response and calling in specialist cells from our tissues and organs. Some of these cells can make antibodies against the virus, some destroy the infected cells, and others build a memory of the virus for next time. Some of the things that make us feel ill – snot, fever and swollen lymph nodes, for example – are due to our body’s battle to get rid of the virus, not because of the virus itself.
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