Dr. Sudhir Mehta discusses the current hot topics concerning COVID-19- lymphocyte count as a marker for the illness plus other significant lab findings to watch out for, and the use of drugs- hydroxychloroquine and azithromycin.
For our comprehensive coverage and latest updates on COVID-19 click here.
Lymphocyte count: Is it a prognostic marker in COVID-19?
Check for lymphopenia on day 1, 7 and 14 in COVID-19 patients. Dengue taught us the value of platelet count interpreted along with haematocrit and COVID-19 is now teaching us the value of lymphocytes in blood test.
It has been a standard teaching that all viral fever will have high lymphocyte count. Low count will only occur with HIV, SARS like illness, measles and hepatitis. Now all studies have shown it to be an important marker of COVID-19.
In the latest study published on March 9, 2020, The Lancet, authors showed that baseline lymphocyte count was significantly higher in survivors than non-survivors. In survivors, lymphocyte count was lowest on day 7 after illness onset and improved during hospitalisation, whereas severe lymphopenia was observed until death in non-survivors.
Clues for COVID-19 include leukopenia, seen in 30 to 45% of patients, and lymphocytopenia, seen in 85% of the patients in the case series from China. Other associated lab findings are elevated alanine aminotransferase and aspartate aminotransferase levels (37%). High D-dimer levels and more severe lymphopenia have been associated with mortality.
Click here to see references
Use of hydroxychloroquine and azithromycin in COVID-19
Hydroxychloroquine (200 mg three times per day) and Azithromycin (500 mg once daily for 10 days)- with no proven treatment and 15% mortality in 80 plus people, 8% in 70 plus people and 3% in 60 plus people it becomes necessary to use of these drugs in treatment.
Chloroquine and hydroxychloroquine have been reported to inhibit SARS-CoV-2 in vitro, although hydroxychloroquine appears to have more potent antiviral activity .
Chloroquine is included in treatment guidelines from China's National Health Commission and was reportedly associated with reduced progression of disease and decreased duration of symptoms [2,3]. However, primary data supporting these claims have not been published .
In an open-label study of 36 patients with COVID-19, use of hydroxychloroquine (200 mg three times per day for 10 days) was associated with a higher rate of undetectable SARS-CoV-2 RNA on nasopharyngeal specimens at day 6 compared with no specific treatment (70 versus 12.5 percent) .
It is reasonable to use one or both of these agents in hospitalised patients with severe infection or those who are at risk of severe infection, particularly if they are not eligible for other clinical trials.
The European Union Clinical Trials Register shows that the Marseille study was accepted on 5th March by the National Medicines Safety Agency (ANSM). It could include up to 25 COVID-19 positive patients, comprising five aged 12 to 17 years, 10 aged 18 to 64 years, and 10 more aged 65 years or over. The unblinded study showed a strong reduction in viral load with Hydroxychloroquine.
After 6 days, the percentage of patients testing positive for COVID-19 who received Hydroxychloroquine fell to 25% versus 90% for those who did not receive the treatment (a group of untreated COVID-19 patients from Nice and Avignon).
In addition, comparing untreated patients, those receiving hydroxychloroquine and those given hydroxychloroquine plus the antibiotic azithromycin, the results showed there was "a spectacular reduction in the number of positive cases" with combination therapy. At 6 days, among patients given combination therapy, the percentage of cases still carrying SRAS-CoV-2 was no more than 5%. 
Click here to see references
Disclaimer- The views and opinions expressed in this article are those of the author's and do not necessarily reflect the official policy or position of M3 India.
The author, Dr. Sudhir Mehta is a Haematology expert.