With inputs from Dr Monica Vasudev

986:  COVID-19 patients have been found to have 27 times higher likelihood than others to have lost their sense of smell. However, they had merely 2.6-fold higher odds of having fever or chills. So then, why are we measuring the temperature as a detection method for asymptomatic COVID-19? Why not measure the smell and taste as the screening method.

987: How Does Antigen Test Work: First category of COVID-19 tests includes RT-PCR, TrueNat, CBNAAT and Antigen test. These tests tend to detect the virus in the body. The second category, the serologic test, is meant to detect antibodies that are produced in the body to protect it against the virus.

Antigen is a substance, or a part of the virus, which triggers an immune response. Presence of an antigen in the nasal or throat swab indicates that the person is infected.

The RT-PCR test involves several steps and yields results within five to six hours. An antigen test, on the other hand, provides results within 30 minutes. An antigen test costs Rs 450 while an RT-PCR costs Rs 2,400.

Several companies have approached ICMR to obtain approval for their antigen test kit; however only one company, SD Biosensor, has received approval, which manufactures Standard Q COVID-19 Ag kit.

An ICMR study has revealed that Standard Q COVID-19 Ag kit can detect an uninfected person as negative in almost 100%. However, it can diagnose only 50% infected persons as positive.

What does it mean? It means that if out of 100 people, 90 are uninfected, and 10 are infected, the test can detect five as positive and rest all as negative. So, while 90 are truly negative, five are false negative.

Because of this, all 95 should undergo RT-PCR test according to experts. ICMR; however, is of the opinion that only those who have COVID-19 symptoms but are diagnosed as negative in antigen test should go for RT-PCR test.

It would be preferable to also identify asymptomatic false negatives as they can potentially spread the disease being unaware that they are positive. (Source: Outlook India)

988: ICMR has got the Tamil Nadu governments approval to investigate the efficacy of the Bacillus Calmette- Gurin (BCG) vaccine in senior citizens in the fight against COVID-19, at its National Institute for Research in Tuberculosis (NIRT).

989: A decreased lymphocyte count in people coming to the hospital with COVID-19 could assist physicians in identifying those at higher risk for intensive care unit (ICU) admission. Patients with lymphocytopenia were found to have a more than 3-times higher risk for requiring ICU care compared with people with normal lymphocyte counts at the time of admission. Acute kidney injury (AKI) also appeared to be more common among people with low absolute lymphocyte counts. 

This study shows that an absolute lymphocyte count <1000 at admission is associated with ICU admission and organ damage. [July 10 International Journal of Laboratory Hematology]

990: Moderna Vaccine Produces Immune Response in Patients

Every person given Modernas COVID-19 vaccine, mRNA-1273, was found to develop an immune response to the virus that causes it. However, some side effects were reported in the 45 people in the phase I study, but there were no significant safety issues. The vaccine resulted in a robust immune response.

Testing of the vaccine is underway in a larger group of people in a phase II trial. Phase III trials are expected to begin in late July. Phase III trials will test the vaccine on an even larger group and are the final step before FDA approval.

The results from the study, led by the National Institute of Allergy and Infectious Diseases of the National Institutes of Health, are published in The New England Journal of Medicine. 

 Modernas vaccine uses messenger RNA, or the mRNA. It carries the instruction for making the spike protein. This is a key protein on the virus surface that allows it to enter the cells when a person is infected. After being injected, it goes to the immune cells and instructs them to make copies of the spike protein, acting as if the cells have been infected with the actual coronavirus. Other immune cells thus develop immunity.

The study divided the participants into three groups of 15 people each. All participants were given two vaccinations 28 days apart; however, each group received a different strength of the vaccine —25, 100, or 250 micrograms.

Every participant developed antibodies that have the potential to block the infection. Side effects following the second vaccination in the 100-microgram group included fatigue, chills, headache, and muscle pains, ranging from mild to moderately severe.

The phase II study includes 300 heathy adults 18-55 years of age, along with another 300 people aged 55 and older. The company says that it hopes to include nearly 30,000 participants at the 100-microgram dose level in the U.S. for the phase III trial. The estimated date of initiation is July 27. [N Engl J Med.  July 14, 2020.]

Dr KK Aggarwal

President CMAAO, HCFI and Past National President IMA