According to a recent article in Nature, many countries are anticipating an immediate response from newly developed antibody tests. These tests are slated to bring relief from the lockdown and restore the economy.
It is acknowledged by scientists that the antibody tests may be useful to control the COVID-19 pandemic, but only at some time in the future. The tests, when improved, may determine whether a person has been exposed and then may be immune to the virus.
However, scientists worldwide are of the opinion that the potential for these tests has not been established. In any event, there are several hurdles that must be overcome.
The Race is On
We are looking at two critical races. One is the long-term search for an effective vaccine. Initial estimates were that a new vaccine would not be available for a minimum of a year.
As of this writing, a company named Moderna has announced that they have developed a drug that appears to be successful after the first human trial. Moderna believes it could have its drug available by January 2021. Yet there are two more trials Moderna will conduct this year that must also be successful. The first trial only examined results from eight patients. The next two trials must involve thousands of patients.
Currently, about ten companies are working feverishly to develop a vaccine.
An update was added today to the ever-growing field of competitors. The University of Washington announced that it had discovered a potent antibody called S309 from a SARS patient who had recovered seventeen years ago. The researchers said that S309 appears to cover the entire range of coronaviruses. The antibody is currently on the fast track for development and testing.
The second race involves antibody kits. There are research labs and biotech companies rushing to develop accurate blood tests. Governments in various countries have purchased millions of kits. They are relying on these kits to help reopen their economy and relax social distancing regulations.
Unfortunately, Great Britain purchased millions of kits only to find that they were under performing.
There are also suggestions that countries use these tests to issue ‘immunity passports’. The passports would allow the passport holder to be exempt from social distancing rules. One drawback to this plan is that currently, antibody tests cannot determine whether a person can still infect others.
But as with most new technologies, it takes a while before the ‘engine is running smoothly’. Therefore, it is no surprise that these tests have been unable to confirm an individual’s exposure to COVID-19.
Even the tests that have been reliable still cannot confirm whether a person has developed an immunity to re-infection. Scientists indicate that it will be a while before the kits come anywhere near their stated goals.
About Antibody Kits
The highest priority will be to develop a test for all essential workers, beginning with front line people in healthcare.
The goal is to find out if they are at risk for infection. The big question remains whether a vaccine can be found to provide immunity for everyone.
Testing the General Population
There are tests being used by teams of researchers worldwide that count a portion of the infections in a certain area. Then they use these results to estimate the overall number of cases in that same area. The researchers value these tests because there are many areas in the world that are not conducting standard testing.
On this note, the US Centers for Disease Control and Prevention (CDC) is reportedly planning a nationwide study in June or July of this year in twenty-five metropolitan areas. Blood from donors will be tested in an effort to examine the spread of COVID-19. The goal of the study is to find antibodies caused by the virus.
Reuters Newswire found out that the CDC is currently collecting blood from donors in five metropolitan cities but has no further details. The CDC has not immediately returned Reuters’ request for comment regarding either study.
About Antibody Tests
The function of the immune system is to produce antibodies against a virus. The antibody kits use elements from a virus called antigens. There are two types of tests:
- lab tests processed by technicians that have results back in one day, and
- tests called point-of-care that produce results in less than a half-hour.
According to health experts, these tests do not identify the actual virus, and therefore are limited in their diagnosis of active infections.
Some experts stress that point-of-care tests are less reliable than tests conducted in labs. The reason is that these tests use a smaller sample of blood (finger prick) and are conducted in an environment that is less controlled than testing in a lab. Therefore, they recommend that these tests be used with caution. The World Health Organization suggests that the point-of-care tests be reserved for research only.
And Now PCR Tests
According to Dr. Edward Wright, University of Sussex, most of the reports they are receiving are a result of polymerase chain reaction (PCR) tests. These tests identify the RNA which is the genetic information of the virus. Such results can only be obtained if the person tested has the infection. But still, we are reminded that the tests are not perfect.
PCR tests detect antigens (foreign substances) rather than detecting antibodies or the body’s immune response. These early results will alert doctors before a person begins to have outward symptoms.
Yet a report from a hospital in China finds that the PCR tests missed diagnosing some patients who had been infected with COVID-19. We are reminded that it took several years before antibody tests showed ninety-nine percent accuracy in detecting HIV.
FDA Eases Testing Rules
The FDA has introduced emergency authorizations governing these tests. It is allowing the use of the tests in laboratories and also by healthcare workers in the diagnosis of COVID-19 infection. However, the FDA also adds the disclaimer that these tests have not been reviewed and therefore they should not be used as the only method of confirming whether a person has COVID-19.
This is just one example showing that most of the kits in circulation have not undergone thorough testing to ensure their reliability. Many tests currently on the market are not accurate enough to identify people with active disease. This is called test sensitivity. Finding people who have not had COVID-19 is called test specificity.
In order for a test to be considered ‘high quality’, it must have a rating of ninety-nine percent specificity and sensitivity. Translated, that means a high-quality test should identify one false positive and one false negative for each one hundred true positive and true negative results.
One doctor said that if they do not have reliable tests, they will do more harm than good.
Timing is Also a Factor
Consider that a test may be conducted soon after the onset of the infection. But at that point, the body has not yet developed antibodies. Therefore, test results would present a false reading.
That fact has been well established but in fairness, scientists have not been able to find out when COVID-19 antibodies develop.
The World is Waiting
Scientists are trying to answer another question: to what extent does a person being infected with the virus create immunity to re-infection?
Immunity is created by a specific antibody (neutralizing antibody) that would prevent COVID-19 from invading cells. To date, there is no clear answer about whether people with COVID-19 actually develop these antibodies.
Re-infection is Another Missing Piece of the Puzzle
Although researchers have said there has been no evidence of re-infection, recently there have been scattered reports of people being re-infected.
One such report came from China where a man had been released from the hospital as he was free of the virus. His neighbors were simultaneously released from their quarantine and were overjoyed upon hearing the news.
They immediately planned a party for him. Several weeks later it was discovered that his virus had returned. He was returned to the hospital and his neighbors were returned to quarantine.
The researchers are basing their opinion on studies using Rhesus monkeys that were infected with the SARS-CoV-2 virus. One month after the initial infection, the Beijing team found that the monkeys could not be re-infected. But emerging cases of re-infection dispute this opinion.
The only definitive answer to these questions is that so far, we have no definitive answer.
