Posted on May 12, 2020, 3 p.m.
Chongqing Medical University China has found that nearly everyone who recovers from COVID-19 will develop antibodies to it; 95% of the patients were found to have had the immune cells within three weeks.
According to the recent research nearly everyone who becomes infected with this virus and goes on to recover will develop antibodies to it; 95% of the 285 patients developed both types of immune cells that fight this virus.
Globally antibody testing is being geared up in an attempt to see who has already had the virus and was able to develop some potential form of natural protection against reinfection from COVID-19. However, many questions remain around these antibodies such as whether everyone will develop them, what level is necessary to confer protection, and just how long the protection if any will last.
This study was designed to help answer one of those question and it “brings much-needed clarity, along with renewed enthusiasm, to efforts to develop and implement widescale antibody testing for SARS-CoV-2,” wrote Dr Francis Collins on the National Institutes of Health's (NIH) Director's blog.
By this point just about everyone has heard about antibodies and knows that they are immune cells that the body develops in a unique response to a given pathogen, and if you have never had exposure to a virus or bacterium you will not develop antibodies to it. In response to most infections the body will start producing these specialized cells that will recognize and target an infection should it occur again, often it will neutralize the pathogen entirely.
Coronaviruses are much like those that cause the common cold, from what is known about other coronaviruses scientists are guessing that humans will develop antibodies against this novel version. Up until recently there was no knowing for sure until they were able to study patients.
In this study the blood of 258 patients was monitored for signs of immune cells; humans produce two types of antibodies Igm and IgG. The first is produced early after infection and these IgM antibodies provide a short burst of protection before fading away; 40% of the patients had produced IgM antibodies within the first week of infection, and after two weeks of observation 95% had developed detectable levels of IgM and were producing IgG antibodies that take longer to develop but have more potential for long term protection.
In a follow up study blood was collected from another 69 patients, and within 20 days all but two patients produced antibodies; those two patients were a related mother and daughter.
To determine how much protection these antibodies carry and for how long they confer immunity scientists will need to continue to study patients and follow them, perhaps even doing challenge experiments to expose them to the virus again to see if their antibodies will protect them from reinfections.
However, until enough time has passed for such studies to be completed these studies are indeed an encouraging sign that the human body is able to learn and develop defenses against COVID-19 after exposure. If this turns out to be the case humanity may be able to develop some form of herd immunity against COVID-19 that would help to keep possible future cases of this virus from reaching epidemic levels as are currently being experienced on a global scale.
“There’s still a way to go with both virus and antibody testing for COVID-19,” wrote Dr Collins. “But as this study and others begin to piece together the complex puzzle of antibody-mediated immunity, it will be possible to learn more about the human body’s response to SARS-CoV-2 and home in on our goal of achieving safe, effective, and sustained protection against this devastating disease.”
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