Lead author author Dr. Muge Cevik of the University of St. Andrews, U.K. said in a statement that the new analysis "provides a clear explanation for why SARS-CoV-2 spreads more efficiently than SARS-CoV and MERS-CoV and is so much more hard to contain". They found that antibodies "were durable" with only "modest declines" emerging at six to eight months, but noted that there was about a 200-fold range in the level of antibody responses among the adults.
One of these studies, for instance, found that antibody levels "waned quite rapidly" after infection in the British population, suggesting a risk of multiple infections, Health24 reported.
"That amount of memory would likely prevent the vast majority of people from getting hospitalised disease, severe disease, for many years", said Shane Crotty, a virologist at the La Jolla Institute of Immunology, with Dr Deepta Bhattacharya, an immunologist at the University of Arizona, believing that it's not an unreasonable prediction to think that these immune memory components would last for years.
"The paper confirms the importance of looking at memory B cells and memory T cells in order to assess immunity and shows the best types of memory cells to look for and the best time to look for them".
For the past nine months, COVID-19 has been spreading from person to person in the USA while scientists and medical professionals scramble to figure out the novel virus' patterns.
New research suggests that infectiousness peaks early in COVID-19 patients, highlighting the need to quickly identify and isolate cases before the virus spreads.
If the same is true with Covid, then a second infection would be milder than the first.
Someone's behavior, or lack thereof, such as poor hygiene and careers such as those in health care could also contribute to superspreading events because of increased contact with many different people.
It is also good news for immunisation programmes, because if the body can provoke a long-term immune response naturally, it should also do so when triggered by a vaccine.
Globally, scientists have been studying the immunity response among people infected with covid-19. "We do not know that for certain yet, but it is encouraging", said Evans.
A study by the University of Oxford finds that people who have had COVID-19 are highly unlikely to contract it again for at least six months after the first infection.
But the results of this study, carried out in a cohort of United Kingdom healthcare workers - who are among those at highest risk of contracting COVID-19 - suggest cases of reinfection are likely to remain extremely rare.