CORONA FACTS and MYTH COVID Surge
Dr K Aggarwal
Table Expert Zoom Meeting on “Will Covid 19 surge come back again?”
Key points from the
- With unlock 3.0,
the people have relaxed, winter is approaching when a new wave is
expected. We have seen that summer had no effect on the number of cases.
- There are six
strains of the coronavirus: L strain (original strain in Wuhan), strains
S, V, G, GR, and GH. Strain G and its related strains GR and GH are the
most common. In North America, the most widespread strain is GH, while in
South America we find the GR strain more frequently. In Asia, where the
Wuhan L strain initially appeared, the spread of strains G, GH and GR is
increasing. Globally, strains G, GH and GR are constantly increasing.
Strain S can be found in some restricted areas in the US and Spain. The L
and V strains are gradually disappearing (Science Daily).
- Up to 30% of
additions/substitution can occur in the same strain. If the virus
undergoes 70% mutation, it becomes a new virus.
- When we define a
surge, we should consider few points: Is it a new mutation? Is it a new
strain? How does a virus behave? Is it a superspreader?
- The surge can be
due to a new virus, same virus but mutated and same virus but local spread
- If surge is due
to a new strain, the mortality may be different and higher initially. If
it is a surge in existing strain, then spread will be high, but mortality
will be low.
- Pandemics are
won by communities.
- In Delhi and
Mumbai, the surge was in downtown, as social distancing and/or face masks
were not adhered to.
- RT PCR detects
viral antigens (E, S, M, ORF, NS, RDRP); if e antigen is negative, no
corona. All labs do not test for all antigens. If the kits test for
multiple antigens, the sensitivity of the test is higher. This will reduce
the chances of false negative result.
- Cohort pooled Ct
value high, this means that the virus is getting attenuated. Ct value
cannot be the only basis of the report (ICMR), it has to be combined with
clinical interpretation; Ct value can change according to the kit used; it
may be operator dependent. The cut-off value must also be mentioned. It is
important for clinicians to know the viral load.
- Family cluster
may have varied symptoms. But, people are not coming forward.
- Prevention is
very important, but it is not 100% preventable; our concern is to also
reduce the mortality. All efforts today are towards reducing the infection
and less effort in reducing the mortality.
- Western models
will not work in India. We should learn from each other about things that
are unique to India.
- It is important
to identify Day 1. CT scan can become positive on Day 3. If RT PCR report
is not available or it may be false positive, then CT becomes important.
Don’t wait for day 5, as complications may set in by this time. One must
act on day 3.