Of vaccines, antiviral drugs, and antibodies
Editor’s note: In a continuing series, local science writer Barry Evans discusses COVID-19 vaccines, antiviral drugs and antibody tests.
Vaccines
Q Why so long before a vaccine is available?
A Vaccines usually take 10 to 20 years from initial discovery to approval and distribution, so the widely-touted timeline of “12 to 18 months” for a COVID-19 vaccine is incredibly fast (and may be overly optimistic).
QEven that seems a long time!
A Remember, vaccines are prophylactics, not medicines. They’re given to otherwise healthy people—usually infants and young people, as protection against potential diseases. You don’t wait for a kid to develop, say, mumps, before injecting the vaccine; you give it before exposure so the child’s body can develop antibodies to the mumps virus. Medicinal drugs, on the other hand, are given to people who are already sick.
Antivirals
Q I hear a new treatment drug is being tested here in Humboldt? A Gilead Sciences’ antiviral drug remdesivir was shown to be somewhat effective during the 2013-2016 West African Ebola virus epidemic, although ultimately not as effective as other treatments. In mouse studies, remdesivir has been effective against both SARS (severe acute respiratory syndrome, 2003) and MERS (Middle East respiratory syndrome, 2012). Currently it’s an experimental drug for use in COVID-19 patients in a study involving a total of about 1,000 patients across the country, including locally at St. Joseph Hospital. The study should be completed in May.
QDoes it work?
A Early days, but it looks promising. For instance, it was given to 125 patients hospitalized for COVID-19 in Chicago, most of whom were severely ill in ICUs. As of the middle of last week, two had died (fewer than expected), while most have shown improvement, with several already discharged.
QHow
does it work? A It inhibits the virus from replicating, either by causing mutations in its RNA or terminating it.
Antibody tests
QWhat are antibody tests?
A These tests, also known as serology tests, look for evidence that the body is responding to an infection by making antibodies, that is, proteins in the blood that counteract specific antigens (see graphic) such as the COVID-19 virus. The beauty of an antibody test is that it tells you whether you’ve been infected with the virus even if you have had no symptoms. Typically, if you’re infected with COVID-19, you won’t know for several days—if, indeed, you’re aware at all. Many people—between 25 and 50%—appear to be completely asymptomatic.
Q How soon after infection will an antibody test know it?
A One particular type of antibody that’s being tested for (immunoglobulin M) develops in the body a couple of days after infection.
Q Why are antibody tests important?
A The idea is that, if you’ve got COVID-19 antibodies, you’re now immune to the virus, in the same way a vaccine protects you against diseases. According to Dr. William Schaffner, an infectious disease specialist at Vanderbilt University, “The immunity afforded by COVID-19 can be thought of as providing bridging protection until we have an effective vaccine available.” If an antibody test shows that you’re immune, you should be able to return to work—otherwise you might be in lockdown unnecessarily. As NY governor Andrew Cuomo put it, “We cannot restart life as we knew it without testing.” Once antibody testing is in general use, it will give researchers a handle on just how virulent the disease is and how widely it’s spread through large populations.
Q What’s the status of antibody tests?
A The FDA approved the first test under “emergency use authorization” two weeks ago. It uses a pinprick of blood and takes 15-20 minutes to give results.
Barry Evans has written “science-lite” books for McGrawHill. His “Field Notes” column has been published by the North Coast Journal since 2008. He can be reached at barryevans9@ yahoo.com.