Covid 19 : Current Knowledge and gaps

Since the beginning of the pandemic with covid-19, We have learned a lot  regarding prevention and treatment. However,  the knowledge Gap exists. Recent JAMA  editorial summarized this for severe covid-19.

 

PREVENTION

Social distancing, frequent hand washing and mask wearing by the general public reduces the transmission  of covid 19. Contact tracing and isolation are the next public implemented successfully in various countries. 

Two vaccines based on mRNA are reported to be 90% effective in preventing COVID 19. (Pfizer and Moderna). 

Astra-Zaneca-Oxford vaccine has also been approved with similar efficacy.

 

MILD DISEASE

Bamlanivimab, recently received emergency use authorization for the treatment of mild to moderate coronavirus by the FDA. 

Indicated in People at high risk for severe COVID-19 or hospitalization, like people who are obese, over the age of 65, or who have an underlying medical condition that puts them at high risk.

It is not authorized for use for patients who are already hospitalized with COVID or who are receiving oxygen therapy

 

SEVERE DISEASE

 

SUPPORTIVE CARE

  1. Non invasive ventilation for patients with COVID-19, including high-flow nasal cannula oxygen therapy works well as with any other ARDS.
  2. Low tidal volumes of 4- to 8-cc/kg predicted body weight and limiting plateau pressure to 30 cm H2O or less.
  3. Sedation and analgesia should be provided at the minimum level required to promote patient comfort and ventilator synchrony. Neuromuscular blockade (with deeper sedation) can be used
  4. Conservative strategy for the administration of fluids, including aggressive diuresis, if needed,  once patients are out of shock (ie, off vasopressors).
  5. Prone positioning for P/F ratio less than 150 unless contraindicated by severe
    hemodynamic instability, pregnancy, open abdomen, or other reasons.
  6. Venovenous extracorporeal membrane oxygenation should be considered if severe gas exchange abnormalities (eg, profound hypoxemia, severe respiratory acidosis) persist despite standard
    interventions, including prone positioning.

 

SPECIFIC THERAPY

  1. Remdesivir has shown to reduce the duration of illness.
  2. Dexamethasone showed survival benefit in patients with COVID- 19 who require oxygen or mechanical ventilation. Other corticosteroids have also shown benefit in patients with severe COVID.
  3. Tocilizumab has been approved in UK for critically ill Covid patients. 

UNPROVEN THERAPIES

  1.  Hydroxychloroquine
  2.  Lopinavir/ritonavir

REMAINING ISSUES

  1. Distinct pathways of injury due to SARS COV 2. 
  2. Ongoing trials are testing a variety of therapies, including aggressive anticoagulation, convalescentplasma, and additional immunomodulatory agents.
  3. Long-term sequelae of the disease

OUTCOMES

More recent data shows outcomes more typical for patients with ARDS, with hospital mortality of 30% to 40%.

HERD IMMUNITY

For COVID-19, scientists believe between 60% and 70% of the population may need to become immune before herd immunity is reached. That means, around 3 million deaths in USA.

MORTALITY CALCULATOR

For patients with severe Covid, british researchers have developed a calculator called 4C. Can be assessed here-

https://isaric4c.net/risk/ 

 

Early prone positioning in mechanically ventilated covid 19 patients improved survival, finds a cohort study. Read more
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