CMAAO Coronavirus Facts and Myth Buster 78

(With regular inputs from Dr Monica Vasudev)

Post lock down surveillance

A surveillance initiative was implemented in Shenzhen, China, to isolate and contact trace people suspected of having the COVID-19 coronavirus. This resulted in faster confirmation of new cases and reduced the window of time during which people were infectious in the community. This potentially decreased the number of new infections arising from each case, revealed a study of patients and contacts over 4 weeks (Lancet Infect Dis. 2020 Apr 27. doi: 10.1016/S1473-3099[20]30287-5).

Cases of large-vessel stroke in young patients with COVID-19

A study published in The New England Journal of Medicine has revealed that large-vessel stroke may be another complication of COVID-19. Over a 2-week period from March 23 through April 7, 2020, 5 patients younger than 50 years of age presented with new-onset symptoms of large-vessel ischemic stroke, wrote Thomas J. Oxley, MD, Mount Sinai Health System, New York, New York. All the patients tested positive for COVID-19. The author mentioned that every 2 weeks over the previous 12 months, their service has treated, on average, 0.73 patients younger than 50 years of age with large-vessel stroke.

All patients presented with signs and symptoms of stroke, including reduced level of consciousness, hemiplegia, and dysarthria. Patients 1, 4, and 5 had COVID-19 symptoms, including cough, fever, and lethargy. Two patients delayed calling an ambulance owing to concerns about going to a hospital during the pandemic. [NEJM]

A study, published in Clinical Infectious Diseases, showed that the majority of patients with SARS-CoV-2 developed robust antibody responses between 17 and 23 days after illness onset, with delayed but stronger antibody responses in critical patients.

Jiuxin Qu, MD, Third People’s Hospital of Shenzhen, Shenzhen, China, and colleagues analyzed data from 41 patients with confirmed SARS-CoV-2 (two back-to-back tests). Patients with mild, moderate, and severe disease were included. IgG and IgM antibodies against SARS-CoV-2 were measured using the iFlash-SARSCoV-2 IgG/IgM chemiluminescent immunoassay kit. According to the instructions, the sensitivity and specificity of the kits was 90% and 95% for IgG, and 80% and 95% for IgM. Combined nucleocapsid protein and spike glycoprotein were used as coated antigens to increase the sensitivity.

Of the 41 patients, 40 (97.6%) patients were positive with IgG and 36 (87.8%) were positive with IgM. The median time of seroconversion after disease onset was 11 days for IgG and 14 days for IgM. The level of IgG antibody attained the highest concentration on day 30, while the highest concentration of IgM antibody appeared on day 18, but then began to decline.

The IgG level of those in the mild and moderate group was still rising on day 28; however, the IgG response of the critical group was found to be significantly stronger than that of non-critical groups within 4 weeks after illness onset (P = 0.0001). For IgM, the fitting curve of the critical group rose above the cut-off value on day 10, peaked on day 23, and then began to decline. The IgM levels of non-critical groups increased above the cut-off value as early as day 5, peaked on day 16, and then decreased.

In the majority of the patients, antibody responses to SARS-CoV-2 were observed during the first 3 weeks of the disease. The seroconversion time of IgG antibody was earlier than that of IgM antibody. The kinetics of anti-SARS-CoV-2 antibodies should assist in epidemiologic surveys, particularly in clinical diagnoses since the immunoassays can efficiently compensate the false negative limitations of nucleic acid testing. [Clinical Infectious Diseases]

Viral Shedding Continues Up to 6 Weeks after Coronavirus Symptom Onset

Patients may continue to shed the SARS-CoV-2 virus for up to six weeks after symptom onset, suggested a small study of recovered COVID-19 patients. In the convalescence period, a trace of virus may still be detected; however, similar to other virus infections, this does not suggest transmission ability of the infected individual.

As reported in Clinical Infectious Diseases, 299 RT-PCR assays were performed (about five tests per patient). The longest duration between symptom onset and an RT-PCR test was 42 days, while the median duration was 24 days. Over the first three weeks following symptom onset, the majority of RT-PCR results were positive for SARS-CoV-2. From week three onward, negative results increased. All tests were negative at week six after symptom onset. The rate of positive results was found to be the highest at week one (100%), followed by 89.3%, 66.1%, 32.1%, 5.4% and 0% at weeks two, three, four, five and six, respectively.

784: What is prolonged shedding

It is nucleic acid conversion time more than 24 days

785: What is the risk factor for prolonged shedding

Patients with longer viral shedding have been noted to be older and more likely to have comorbidities such as diabetes and hypertension.

From a public health perspective, experts state that there is a need to emphasize that the public should not be scared by those seemingly prolonged positive cases. It is much harder to prove no transmission ability than potentially transmissible.”

What does 14 days isolation means

People must understand that a 14-day isolation is appropriate for seeing if one will go on to develop symptoms after a known exposure to an infected person. Fourteen days is not a sufficient amount of time to be infected, recover and then be virus free.

787: What is the HCW return policy

Dr. Robert Quigley, Senior Vice President and Regional Medical Director of International SOS, noted in an email to Reuters Health, “The question that remains is how great does the viral load need to be to infect another person if in fact the viral load actually decreases over time. Regardless, until this virologic feature is defined, it is clear that infected healthcare professionals (HCPs) should have two consecutive negative tests before returning to the healthcare arena where they could potentially infect a fragile patient.” [Medscape]

When should non-HCPs return to the workplace after testing positive for COVID-19

The absence of symptoms may not annihilate the risk of transmission to co-workers for up to 42 days following the onset of symptoms. This could clearly impact our present practices of quarantine and isolation. [SOURCE: https://bit.ly/358QIJc Clinical Infectious Diseases, online April 19, 2020.]

Confirmation of COVID-19 in Two Pet Cats in New York

The U.S. Centers for Disease Control and Prevention (CDC) and the United States Department of Agriculture’s (USDA) National Veterinary Services Laboratories (NVSL) announced the first confirmed cases of SARS-CoV-2 infection in two pet cats. These are the first pets in the United States that have tested positive for SARS-CoV-2.

The cats belong to two separate areas of New York state. Both had mild respiratory illness and are expected to make a full recovery. SARS-CoV-2 infections have been reported in very few animals across the globe, mostly in those that had close contact with a person with COVID-19.

Routine testing of animals is currently not recommended. If other animals are confirmed positive for SARS-CoV-2 in the United States, USDA will post the findings. State animal health and public health officials will determine whether animals should be tested for SARS-CoV-2.

  • In the NY cases, a veterinarian tested the first cat after it exhibited mild respiratory signs. None of the members in the household were confirmed to be ill with COVID-19. The virus seems to have been transmitted to the cat by mildly ill or asymptomatic household members or through contact with an infected person outside its home.
  • Samples were obtained from the second cat after it showed signs of respiratory illness. The owner of the cat tested positive for COVID-19 before the cat showed signs. Another cat in the household has no signs of illness.

Both cats tested presumptive positive for SARS-CoV-2 at a private veterinary laboratory and the result were reported to state and federal officials. The confirmatory testing was done at NVSL and included collection of additional samples.

The World Organisation for Animal Health (OIE) considers SARS-CoV-2 an emerging disease, and therefore USDA is required to report confirmed U.S. animal infections to the OIE.

Public health officials are still learning about SARS-CoV-2, but there is no evidence that pets have a role in spreading the virus in the United States. Taking measures against companion animals that may compromise their welfare therefore does not seem justified. Further studies will help understand if and how different animals, including pets, could be affected.

CDC recommends the following, until more information is available:

  • Do not let pets interact with people or other animals outside the household.
  • Keep cats indoors when possible to prevent them from interacting with other animals or people.
  • Walk dogs on a leash, maintaining at least 6 feet from other people and animals.
  • Avoid dog parks or public places where a large number of people and dogs gather.

If you are sick with COVID-19 (either suspected or confirmed by a test), limit contact with your pets and other animals.

  • When possible, have another member of your household care for your pets while you are sick.
  • Avoid contact with your pet, including petting, snuggling, being kissed or licked, and sharing food or bedding.
  • If you must care for your pet or be around animals while you are sick, wear a cloth face covering and wash your hands before and after an interaction with them. [CDC]

Dr KK Aggarwal

President CMAAO, HCFI and Past National President IMA

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