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Have a question about coronavirus, also known as COVID-19?

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Send questions to tribdem@tribdem.com.

If a person had COVID-19 in the past, lets say in February, and takes the testagain in May, is the test going to show negative? In other words you could have hadcoronavirus in the past and it would test negative now?

So, the only way to find out if you had it in the past would be the antibody test, correct?

The answer:

Great questions, and it all comes back to testing and more frequent testing. Theres some very recent positive data out of South Korea which Ill discuss below.

Your questions refer to the different types of tests. One test is the molecular swab (Polymerase Chain Reaction PCR), which detects genetic RNA from SARS-CoV-2, also known as the COVID-19 virus. The other test is a blood IgG antibody, which determines if someone was previously infected, or was recently exposed to the virus 10-21 days ago.

If you had COVID-19 infection in February, the PCR swab test would probably be negative now, and the blood IgG antibody test would probably be positive (indicating prior infection). Recent data out of South Korea suggest that if the repeat PCR swab test is positive, that may be detecting dead virus, rather than indicating reinfection. And the positive IgG antibodies may provide some protection.

Because the pandemic is only a few months old, there is no data on long-term immune response.

Dr. David Csikos, chief medical officer, Chan Soon-Shiong Medical Center at Windber.

When older adults fly, canthey get tested upon arrival sothey dont need to be secluded for 14 days?

The answer:

The tests that are available on the market are antibody tests and SARS CoV-2 genome tests.

The antibody tests show if a person is having an adaptive or specific response to the virus; the genome test is indicative of an active infection, as viral RNA is present. These tests, particularly the genome test, give a snapshot of what is happening on that day.

Individualswho are exposed to SARS CoV-2 wont show symptoms for five to seven days, on average. A test upon landing would not be sufficient to say that the individual is not in the incubation period of COVID-19.

Theperson could have been exposed to the virus on the plane. This is why the 14-day quarantine is recommended.

Jill D. Henning, associate professor of biology, University of Pittsburgh at Johnstown.

My husband and I tested positive in March, then aftertwo weeks, we had no symptoms. We got retested last week and are both positive. Why would this happen?

The answer:

An excellent question that has relevant implications.

I assume the tests were molecular PCR (Polymerase Chain Reaction), which detects genetic RNA from the COVID-19 virus. If you and your husband dont have any symptoms or fever, this implies both are now asymptomatic carriers. It is not known how long you will remain a carrier without symptoms, and that may depend in part how long protective immunity will last.

I recommend you and your husband consider blood tests for IgG antibodies to SARS-CoV-2.

It is unknown if both are still contagious, and thats why its important to wear face masks in public and continue social distancing. While the evidence on reinfection is evolving, current data and experience from previous viruses without substantial seasonal mutation do not support this hypothesis.

Because the COVID-19 pandemic is only a few months old, there is no data on long-term immune response. It is also controversial when asymptomatic carriers may return back to work. I recommend both of you follow up with your primary care physician, and if necessary, consult an infectious disease specialist.

Dr. David Csikos, chief medical officer, Chan Soon-Shiong Medical Center at Windber.

I have read that scientists are working on testing community spread by testing water from the sewer.

Would it be possible to develop individual urine tests (akin to pregnancy testing)that could inform a person positive or negative for the virus on a daily basis?

The answer:

To my knowledge, there are only two kinds of tests for SARS CoV 2, a genomic RNA test and an antibody test. The RNA test is looking for viral genetic material in patients and the antibody test is looking for the presence of an immune response to the virus.

SARS CoV 2 has been detected in feces of infected patients, but it is not clear whether that virus is infectious. In addition, waste water has been shown to contain the virus, but standard municipal sanitation practices or use of a septic tank has been shown to inactivate the virus.

Urine contains waste products from the human body that can be dissolved in water. Hormones, sugar, vitamins and certain proteins can be found in urine. RNA and DNA can be found in urine as well.

Urine tests,such as those you mention in your question, require a high concentration of the substance to be in the urine.

A recent study out of China was able to detect SARS CoV 2 in urine of one patient out of 17 with confirmed disease. Other peer reviewed studies were unable to find viral RNA in urine. These studies used a technique called RT-PCR to detect the viral RNA. This technique amplifies minutely small quantities of viral RNA and brings the concentration up to detectable levels.

Who knows what the future holds? That is the beauty of science. But at present, we do not have the ability to detect the minuscule amount of viral RNA in urine without amplifying it first.

I am a cashier at Walmart. I had something similar to COVID-19 in December, however no breathing problems. Am I safe to visit my 2-week-old grandson? I shower, wash my hair and wear clean clothes and wash my hands when visiting. I also work daily, sanitize frequently and wash my hands every chance I can. I also wear a mask when working and visiting. Am I putting my grandson in danger?

The answer:

Social distancing is hard and it must be truly difficult when a new family member is born.

When we are first born and until we are about a year old, our immune systems are immature. The responses we build to microbes takes time and the littlest among us have not been around long enough to have the same responses that adults or even older children do. This makes infants more susceptible to infections.

In a recent study out of China, of more than 2,100 children with suspected or confirmed COVID-19 in between late December and early February showed that about 11% of infants had severe or critical illness. Children in other age groups had lower rates of severe or critical illness (about 7% for children ages 1 to 5, 4% for ages 6 to 10, 4% for ages 11 to 15).

Other studies are showing an inflammatory illness that may be linked to COVID-19. This response that is seen in children is severe and rare. It has to deal with an immune response that leads to a cytokine storm. Our innate response, the one we are born with, has the ability to make our blood vessels leaky in order to let white blood cells into our tissues where the infection is. It does this by releasing cytokines, proteins that allow the immune system to communicate with cells and tissue of the body. This response is usually localized, but in some children it becomes systemic causing the blood vessels all over the body to be leaky; this results in severe symptoms such as organ failure and shock.

From your question, it appears that you are doing things to reduce your risk of infection. If you feel that you had COVID-19 in December, I urge you to request an antibody test. This could help determine if you did have COVID-19.

With respect to visiting your newborn grandson, I support respecting the community directed stay-at-home orders. He is still developing his immune system and is in a risk group because of his age. You and your family can speak with the childs pediatrician to see what the case counts are in your area and then determine what level of risk is acceptable to you as a family.

Jill D. Henning, associate professor of biology, University of Pittsburgh at Johnstown.

Can you be a carrier ofCOVID-19 and not have any symptoms as in youre immune to the virus but still carry and spread the virus?

The answer:

Yes, there are asymptomatic carriers, however no one can truly determine the impact of asymptomatic cases on spread until theres more testing.

Can these people who are completely asymptomatic, who never develop any symptoms, transmit the infection? Thats still an open question, and no one knows for sure. Experts say these carriers without symptoms make it even more important for people to wear face masks in public.

Dr. David Csikos, chief medical officer, Chan Soon-Shiong Medical Center at Windber.

I was really sick with upper respiratory turned into bronchitis turned to pneumonia in late December to middle of February. Is it possible I had COVID?Would an antibody test still show antibodies if I did? I had almost all the symptoms.

The answer:

When did SARS CoV-2 emerge?

That is one of the big questions of 2020.

Science uses a method called the molecular clock to determine when new pathogens emerge.

SARS CoV-2 is an RNA virus. Ituses an enzyme to copy itself called RNA dependent RNA polymerase. This enzyme is sloppy in its copying. The rate of mistakes it makes is able to be tracked.

Using this technology, scientists at the Imperial College of London collaborated withthe World Health Organization to determine that SARS CoV-2 emerged between Nov. 6 and Dec. 13 in Wuhan, China. Couple the new respiratory virus with the ability to be anywhere in the world in 24 hours and ...

Testing can help sort out whether a person has recovered from COVID-19. The test that will determine if a person has had an immune response to the infection is the antibody test. IgG antibodies are present in a person aftershe or he has had an infection that resulted in an adaptive (specific) immune response.

If you are curious about your status, you can seek out an IgG antibody test. The more data that can be acquired about positive cases, in any stage, will help answer the question of when. It is possible, however, that we will never know when it emerged.

Jill D. Henning, associate professor of biology, University of Pittsburgh at Johnstown.

I am wondering how it could be possible to see my significant other during the coronavirus pandemic. We live separately, and I have been quarantined while he has continued to do basic things such as grocery shop and goes to work two times per week, always following recommended precautions. We are wondering if he were to do a PCR test for coronavirus RNA combined with an IgG and IgM antibody test, could this provide a sufficient picture upon which to base a decision to see one another, or not?

The answer:

Social distancing is so hard! All of us have someone we want to see.

In public health there is something called risk reduction. It refers to using strategies that minimize the risk or harm certain human behaviors come with for example, wearing a bicycle helmet when riding a bike. If you wear a helmet, you are less likely to have a traumatic brain injury if you wreck. You still ride the bike, just in a safer way.

With SARS CoV-2, becoming more lax on your social distancing is not the same as wearing a bicycle helmet when riding a bike. SARS CoV-2 is spread via airborne droplets by people who may not know they are sick yet. Even people who are practicing social distancing may not know they have been exposed because they could have come in contact with people who dont know they are infected yet.

Testing can help. The test for genomic RNA of SARS CoV-2 will let a person know ifhe or she is actively infected at that time. The antibody tests would show that you are in the first stages of an adaptive immune response (IgM) or that you are in the later stages or recovered from COVID-19 (IgG).

However, this is only a snapshot of the infection risk. It only says that at the time of the test, the individual is SARS CoV-2 free. If that individual goes out in the community the next day, he or she could be exposed to someone with the virus and become infected.

Until we have more testing,two-thirds of our population recovered, or a treatment is found, it is best to keep socially distant.

As always the risk assumption is yours; however, the recommendation is to maintain social distance.

Jill D. Henning, associate professor of biology, University of Pittsburgh at Johnstown.

Are drug users, especially intravenous, more likely to spread COVID-19 or other viruses and diseases than non-drug users?

The answer:

SARS CoV-2 is spread via respiratory droplets. Anyone can spread the infection if they have symptoms and we are seeing studies that show asymptomatic transmission in about 35% of individuals (recent studies from the New England Journal of Medicine).

Now is a good time to remind everyone that human behavior contributes to the spread of any infectious disease. When we consider COVID-19, we can reduce the spread by wearing a mask in public, washing our hands, and maintaining social distance.

Injection drug users are at a greater risk for blood-borne pathogens, such as Hepatitis and HIV, as well as having a greater risk for sepsis, a bacterial infection in the blood. As for other drug users, according to the National Institute of Allergy and Infectious Diseases, because SARS CoV-2 attacks the lungs it could be a serious threat to those who smoke tobacco or marijuana or who vape. People with opioid use disorder and methamphetamine use disorder may also be vulnerable due to those drugs effects on respiratory and pulmonary health.

In short, anything that decreases lung functioning can lead to more severe COVID-19 disease.

Jill D. Henning, associate professor of biology, University of Pittsburgh at Johnstown.

I am a nanny and was asked to enter the familys home wearing a mask. I assumed they (mom, dad and 41/2-year-old) would also be wearing masks. They did not. I wear one to protect them and vice-versa, correct?

The answer:

There are no formal guidelines on what should be done in this situation. Childcare is a necessity for many families, even if they are working from home. In this situation, I would recommend that you all (mom, dad, child and nanny) keep each other apprised of your health situation. Have a discussion about your exposures and risk factors for SARS CoV-2 (for example, do you live in a home with an essential worker) be truthful about each others movement (or lack there of) in the community. If you are nannying for another family, be sure to inform all parties involved.

After this conversation, decide together on a safety plan that makes everyone comfortable.

For example, everyone has their temperature taken daily before work starts. If symptoms become apparent, all are notified.

Maybe you have certain rooms that are for family only in the home, maybe you and the child remain in one area of the home.

Through working together as a unit, you can be sure to address all concerns and come to an agreement in which everyone feels safe.

Jill D. Henning, associate professor of biology, University of Pittsburgh at Johnstown.

The news keeps saying people under 18 rarely transmit the disease. However, what evidence is this based on? I read that children under 18 dont get the disease, or very mildly and dont transmit. But how many children have had the disease? How many children under 18 have actually been tested? If we do not have facts on children under 18 how can we say that they rarely get it and they do not transmit it?

The answer:

We dont have all the facts yet on how COVID-19 affects different populations, or know how many people have had the virus. And this is especially true with children.

It seems that children may not have symptoms that are severe, but we do know they get the virus. There have been a few cases (not locally) where kids are intubated, and respirators were used for children. Children can still pass the virus to their older family members who can have much more severe symptoms.

Everyone, including children, should follow the recommended precautions to prevent the spread of the virus.

Originally posted here:
Experts answer your COVID-19 questions: 'If a person had COVID-19 in the past, let's say in February, and takes the test again in May, is the test...

This entry was posted on May 22, 2020 at 8:48 am and is filed under Genetic medicine. You can follow any responses to this entry through the RSS 2.0 feed. Both comments and pings are currently closed. |