Over the past year, scientists have been studying the coronavirus and developed a vaccine at a record pace. During an infection, our immune system develops a healthy response, leaving us with antibodies. But in severe cases, it can end up going overboard or not working at all.
First, the good news:
Immune responses fall on a spectrum. Our bodies develop lifelong immunity to viruses like hepatitis A or measles, while HIV, on the other end, can evade our bodies’ defenses for as long as we live. 'Fortunately, SARS-CoV-2 is closer to the hepatitis A end of the spectrum,' says Andrea Cox, a viral immunologist at Johns Hopkins University. 'It's not the easiest virus, but it's nowhere near HIV.'"
In June, researchers found that our immune system produces antibodies as well as killer/helper T cells, which kill infected cells and help make more antibodies. Further experiments concluded that the antibodies did indeed prevent the virus.
"As part of their ongoing COVID-19 testing program, they performed screening for a commercial fishing boat, collecting blood samples before and after the voyage to track antibodies. Most of the 122 people on the fishing boat tested positive for the coronavirus on the return to shore—but none of the three crew members whose blood had antibodies against SARS-CoV-2 before departure were infected on the trip. Thanks to a bit of luck and clever design, the published study was the first to show that having antibodies likely protects from infection."
However, the bad news is that not everyone may develop effective antibodies or have an effective immune response to the virus. A protein called type I interferon primes the body for an immune response before any antibodies are made. However, COVID-19 is good at avoiding and fooling these proteins, leading to a weaker immune response and weak/no antibodies. Afterward, when the body finally discovers the invader, it can overreact and cause more harm than good.
"'You get short-term protection, but it may be at the price of some short-term autoimmunity as well because there's not a lot of regulation there. Everything goes,' says Iñaki Sanz, an immunologist at Emory University who studies autoimmune diseases. Sanz has shown in a study that some severe cases have exactly this response, turning the immune system against its own body, akin to what happens with autoimmune diseases such as lupus."
In the future, scientists look to solve lingering questions about reinfection and the effectiveness of the vaccine in long term protection.
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