A question that has been appearing for a while is—whether novel Coronavirus infected people, which include US President Donald Trump, are immune from reinfection and if so, then how long the immunity lasts. To determine the answer, scientists at the University of Arizona conducted a study and found that the immunity against COVID-19 may last for several months.
The researchers at the University of Arizona studied the production of antibodies from a sample of nearly 6,000 people infected with the SARS-CoV-2. As per their findings, the immunity may persist for at least five months after being infected with the novel virus.
Deepta Bhattacharya, associate professor at the University of Arizona said that through the study they have noticed that "high-quality antibodies still being produced five to seven months" after the Coronavirus infection. In addition, he said, "We used this study to investigate that question and found immunity is stable for at least five months."
The Virus and Immunity
After the virus invades the cells, the immunity system releases short-lived plasma cells capable of producing the antibodies to fight against the pathogen, explained the researchers. After the research was conducted, Bhattacharya and the co-author Professor Janko Nikolich-Zugich from UArizona also said that antibodies appear in blood tests within 14 days of infection.
The creation of long-lived plasma cells is the second stage of the immune response that produces high-quality antibody levels over the next few months in Coronavirus-infected people. As per the study, which was published in the journal Immunity, the researchers noticed the presence of Coronavirus antibodies in the blood tests, at viable levels, for five to seven months. But they believe that the immunity lasts much longer than that.
UArizona Health Sciences Senior Vice President Michael D Dake said, "whether antibodies provide lasting protection against SARS-CoV-2 has been one of the most difficult questions to answer." He also added that this study not only has given the researchers the ability to accurately test for antibodies against the Coronavirus caused disease but also has "armed us with the knowledge that lasting immunity is a reality."
Previous studies estimated the antibody production from initial infections and suggested that the levels of the antibodies drop quickly after the infection—causing a short-term immunity against COVID-19. But as per Bhattacharya, such conclusions were focused on short-lived plasma cells and have failed to consider long-lived plasma cells, as well as high-affinity antibodies they produce.
He also noted that "the latest time-points we tracked in infected individuals were past seven months, so that is the longest period of time we can confirm immunity lasts." As per the researcher, the SARS infected people—a virus from the same Coronavirus family—are still seeing immunity 17 years after infection. So, if the novel Coronavirus is anything like the first one, "we expect antibodies to last at least two years, and it would be unlikely for anything much shorter," said Bhattacharya.
Nikolich-Žugich said that the research team has now successfully tested almost 30,000 people in Arizona. Antibody tests are available for anyone in Arizona from the age of 18 at locations around the state. People can also visit https://covid19antibodytesting.arizona.edu/ for more Coronavirus information and to sign up for testing.