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Thursday, 24 September 2020

Q&A: Tests, treatments and vaccines – an immunologist discusses COVID-19

Professor Richard B. Kennedy of the Department of Internal Medicine at the Mayo Clinic explains the different kinds of tests being used and the different treatment prospects for the virus

Ashraf Amin, Friday 27 Mar 2020
Professor. Richard B. Kennedy
Professor. Richard B. Kennedy
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Ahram Online spoke to Professor Richard B. Kennedy, associate consultant at the Department of Internal Medicine at the Mayo Clinic in the USA, about recent updates in the medical research aimed at tackling the coronavirus.

 

Ahram Online: What is the chance that a recovered case could transmit the disease?

Richard Kennedy: Most people can still transmit the disease for a short period of time after they are feeling better. Because of this, we are defining “recovered cases” as those who test negative for the virus on two separate tests taken 24 hours apart. If the patient does not have the virus in them, they cannot transmit the disease. It is possible that patients can have a very low level of virus that is not detected by our tests.

However, the good news is that the amount of virus in the patient’s lungs is directly related to how infectious they are. Right now we believe that the chance of a recovered patient transmitting the virus is low.

AO: What is the difference between the different kits for COVID-19 detection? 

RK: There are two main types of kits. The first are called molecular assay (or PCR assays). These are designed to detect the RNA that is found inside each viral particle. The use a process called Polymerase Chain Reaction to rapidly [make] millions of copies of short pieces of RNA found only in the virus. We then look for the presence or absence of this RNA. These kits are very sensitive and can detect a little as a few thousand viral particles per ml of blood.

Recently, our research teams developed a new PCR test that is currently submitted for review and authorisation. We hope that these kits would ease some of the burden on the main laboratories in the different countries of the world.

The second type of assay is a serological test. These assays look for the presence of antibodies in the blood that can attack the virus. It takes several days to a week for your body to produce these antibodies after you are infected. Because of that delay, it may not be as sensitive in detecting people who were recently infected.

AO: Regarding the clinical trials of drugs, how long it will take for FDA approval? 

RK: These trials are just starting so it will take some time to find out if these drugs really do work. The FDA has streamlined its approval process for the clinical assays and is likely to be doing the same thing for its drug approval process. If early results are promising, sometimes drugs can be used under Emergency Use Authorization. 

Normally, there are four phases of clinical trials. Phase 1 trials are small studies that focus on patient safety. Phase 2 trials focus on efficacy (does the drug work?). Both of these are small scale studies. If a drug successfully completes these trials, it will move on to Phase 3. In a Phase 3 trial, we study the same questions “Is it safe?” “Does it work?” But we do so in much larger populations, including groups who are at high risk of infection. When a drug successfully finishes a Phase 3 trial, it can be ready for regulatory approval and mass production. Phase 4 trials typically happen after a product is commercially available and can involve tens of thousands of people. The intent of these trials is to look for long-term safety and/or rare side effects.

AO: Knowing that the vaccine approval may take between 12 to 18 months, is there a way to speed up the approval of vaccines? 

RK: Yes. Regulatory approval processes can be streamlined – most countries are now doing this. Some vaccines (e.g. live virus and whole inactivated virus) require a lot of time and effort to create, while other vaccines (e.g. protein, RNA) can be produced more quickly. We learned a lot about immune responses to coronaviruses during the SARS and MERS outbreaks in 2003 and 2012 respectively. That significantly speeds up the process since we do not need to develop new detection assays, new animal models, or other basic tools to test new vaccines.

AO: With respect to the research efforts globally, what could be the forecast scenarios if the COVID-19 virus mutates during the approval process of new drugs and vaccines? 

RK: All coronaviruses are RNA viruses (like influenza). RNA viruses have very high mutation rates. When they copy their genetic information, they make mistakes often. Early reports indicate that this virus mutates about once a month. Occasionally a mutation may make the virus resistant to a drug. One way to prevent that is to use multiple drugs at the same time – it is less likely that the virus develops multiple mutations to resist many drugs simultaneously. 

Vaccines are another potential solution. A vaccine typically creates an immune response to multiple parts of a virus, making it difficult for the virus to mutate all of those parts at the same time.

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