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Doctors in the intensive care unit at Tygerberg Hospital explained in the South African Medical Journal how they are treating patients with Covid-19. (Photo: Ashraf Hendricks)
The report also shows how ICU doctors at Tygerberg Hospital manage patients.
First published by Ground and Spotlight
This is the third number of Covid-19 Report. We present to you the latest quality science on the pandemic. If you come across unknown terms, there is a glossary at the end of the article.
Promising new evidence
Generally speaking, there are three types of tests for an infection like Covid-19:
- Those who check the genetic material of the virus. These are known as PCR tests. In South Africa, when testing for Covid-19, this is what is currently used. The advantages are that they are reliable and indicate if you are currently infected (although only a few days after being exposed). The disadvantages are that these are mostly long and expensive.
- Antigen tests: they detect fragments of viral proteins. The FDA has granted the use of emergency authorization (which is not the same as approval) for the first such test, conducted by Quidel Corporation. The advantages are that it is cheap (around $ 5 according to one source), it gives results in 15 minutes (but as far as we can tell, we are not sure, it has to be done in a laboratory), and Quidel can quickly start producing millions of they. If your result is positive, you are almost certainly currently infected. But the downside is that it has a high false negative rate. In other words, it may be infected, but the test may say that it is not.
- Antibody tests, on the other hand, detect if you have been previously infected with Covid-19. These should give a positive result even after you have recovered. They are generally less expensive to manufacture and generally give faster results than PCR tests. This is vital for surveillance, to see what percentage of the population has been infected. From this we can learn how fast the virus spreads and how much immunity people have against reinfection. But they don’t tell you if you are currently infected.
Until now, the precision of antibody tests has been too low and this has resulted in some low-quality surveillance studies that have wide media coverage.
A study published in Nature He found that each person infected with SARS-Cov-2 (the virus that causes Covid-19) develops a type of antibody called Immunoglobulin G, within 19 days of the onset of symptoms. The antibodies developed appear to be specific to this virus. So in theory we should be able to get closer to perfect precision antibody testing.
Swiss-based pharmaceutical company Roche claim (is has developed a test that detects antibodies to SARS-Cov-2 with 100% accuracy if it has them (that is, without false negatives), and with more than 99.8% accuracy it detects when it does not have them (that is, very few false positives), provided that at least 14 days have passed since a PCR test had shown that you are infected. It also claims to be able to produce more than ten million tests as of this month. The FDA has granted Roche’s “Emergency Use Authorization” test (again, this does not mean that the agency has approved the test). It remains to be seen whether Roche promoted his claims or made a breakthrough.
Another modest drug test result
Last week we reported on the modest findings on the drug remdesivir. Now The lancet has published results from a clinical trial in Hong Kong comparing two drug regimens: interferon beta-1b, ribavirin, and the anti-HIV drug lopinavir-ritonavir versus lopinavir-ritonavir alone. The study compared the time it took for patients on each regimen, all with mild to moderate Covid-19, negative, in other words, officially recover. It took an average of seven days for patients on the more intensive regimen versus 12 days for patients on lopinavir-ritonavir alone (since starting treatment). None of the 127 trial participants died.
As noted by a South African pharmacologist: This trial did not have a placebo arm or a standard care arm (lopinavir / ritonavir is not known to treat Covid-19, although see below). In addition, the endpoint was virological (result of the PCR test) rather than clinical (how well the patients were doing).
On the same day, the result of a lopinavir / ritonavir trial was published in the NEJM, and found no benefit (or harm). Here the end point was clinical rather than virological improvement.
Taken together, these two studies suggest a very modest benefit for the three-drug regimen. It remains to be seen if there are enough benefits for this regimen (or remdesivir) to become part of standard practice. We are not convinced
Kick back for hydroxychloroquine?
A analysis published in the NEJM of 1,446 patients with Covid-19 at a New York medical center, 811 of whom received hydroxychloroquine, showed no benefit in using the drug.
It is not a clinical trial, just an observational study, and this does not necessarily mean that it is the end of the road for hydroxychloroquine and Covid-19. Furthermore, patients who received the drug tended to be sicker.
But it does suggest that if hydroxychloroquine helps, its benefits will be modest. A well-managed clinical trial that provides more definitive information on the drug’s safety and efficacy is still needed.
That test may have been done now. A not yet peer reviewed study of 150 patients in China No time difference of negative results was found for people with mild and moderate Covid-19 taking hydroxychloroquine compared to not taking it. There were more adverse events in the hydroxychloroquine patients. It’s a small number of patients, and the document needs more scrutiny, but it doesn’t look promising for hydroxychloroquine.
Coronavirus and the common cold
A single paragraph of a Article in the last issue of Science it is full of useful information:
“Coronaviruses are single-stranded RNA viruses that infect vertebrates and move between different host species. With the emergence of SARS-CoV-2, there are now seven coronaviruses known to infect humans. Four of them (HCov -229E, HCoV-OC43, HCoV-NL63 and HCoV-HKU1) are responsible for ~ 30% of cases of the common cold in humans, two of which caused recent epidemics that had considerable associated mortality: SARS-CoV-1, which emerged in 2002-2003 and causes ~ 10% mortality, and the Middle East Respiratory Syndrome coronavirus (MERS-CoV), which emerged in 2012, is still present, active, and causes ~ 35% mortality.
“Both epidemics affected a relatively small number of patients compared to Covid-19, which is more transmissible for various reasons, including asymptomatic carriers, long latency period, and high infectivity. Before Covid-19, only SARS-CoV-1 and MERS-CoV caused serious illness. Therefore, the discovery of coronaviral drugs has been a small effort relative to that of other viral diseases such as influenza. “
From south africa
The MRC weekly update It still shows that the number of recorded deaths (7,135) for the last week for which data is available, April 22-28, is less than the expected deaths (7,319 to 8,494). Natural deaths are as expected, but deaths from homicide and car accidents have decreased.
***
The NICD has published a very good article about who should get a flu shot this year: “pregnant women, children ages 6 months to 5 years, people 65 and older, people with chronic medical conditions like HIV, heart or lung problems, and healthcare workers.”
The jab does not protect against Covid-19 at all. But it does reduce the risk of getting Covid-19 and the flu. If people get vaccinated, it will also reduce pressure on the health system.
***
The NICD also published the second number from his very useful weekly summary of epidemiology Covid-19. One of the many interesting curiosities is that, in terms of tests per 100,000 people, the Western Cape (788) is still far ahead of Gauteng (560), KwaZulu-Natal (407) and the Eastern Cape (369).
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A letter in the SAMJ by several doctors at Tygerberg Hospital describe how they are treating very sick Covid-19 patients. The first six patients in the intensive care unit received ventilators; All died. “Following international reports of improved survival rates with noninvasive ventilation, ICU Covid-19 in Tygerberg … changed its standard operating procedure in mid-April 2020 from ‘early intubation and mechanical ventilation’ initially promoted to oxygen from High flow nasal cannula therapy, “to avoid intubation.” One in seven patients died. This is a small number of patients and this was not a clinical trial or study, but the results are promising.
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Other letter in the SAMJ warns that placing people living on the street in temporary shelters as part of the blockade increases the risk of overdose among people dependent on heroin. DM
Glossary
- Fda (Food and Drug Administration) – United States government organization responsible for authorizing or approving the use of medications.
- Hydroxychloroquine: A drug used to treat malaria, rheumatoid arthritis, and other conditions.
- MRC (Medical Research Council): South African state research institution.
- Nature: Leading scientific journal
- NEJM (New England Journal of Medicine) – Leading medical journal based in the United States.
- NICD (National Institute of Communicable Diseases): South African state institution responsible for treating infectious diseases such as tuberculosis and Covid-19.
- Remdesivir: Antiviral drug made by Gilead Sciences.
- Science: Leading scientific journal
- The lancet: Leading medical journal published in the UK.
Read the previous issues of Covid-19 Report.
* This article was produced by Highlight – health journalism in the public interest. Do you like what you are reading? Sign up for our newsletter and stay informed.
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