Omicron, should I expose myself?

Link to free download of my 2 textbooks

Physiology book in hard copy

Pathophysiology book in hard copy

US variants data

US omicron history

November 29

Index patient, 48 year old unvaccinated man, Nigeria

Nebraska, 6 people diagnosed by PCR and genomic sequencing

Onset was 73 hours (range = 33–75 hours)

Incubation period

Original version, five days

The Delta variant, four days

Omicron, 2 to 3 days

Viral Load

Alpha and Delta variants

Peak viral load 3 days after infection

Clear the virus about six days after that

Infectious viral load in unvaccinated and vaccinated patients infected with SARS-CoV-2 WT, Delta and Omicron

Omicron and Delta produced similar levels of infectious virus

Infections a day shorter with omicron compared to delta

Omicron infects upper airways as opposed to lungs

Omicron antibodies neutralise delta virus

Offshoot of Omicron variant, England

BA.2 may be even more contagious than original omicron

UK Health Security Agency

Designating BA.2 a variant under investigation

increasing numbers of BA.2 sequences identified both domestically and internationally

May have an increased growth rate over BA.1

Vaccine effectiveness with omicron

After a 2-dose primary course of vaccination

Vaccine protection against mild disease has largely disappeared by 20 weeks after vaccination

After a booster dose

Protection initially increases to around 65 to 70%

but drops to 45 to 50% from 10+ weeks

Therefore

It is therefore likely that current vaccines offer limited long-term protection against infection or transmission.

Protection against severe disease

Vaccine effectiveness against hospitalisation is estimated at 92%

and remains high at 83% 10+ weeks after the booster dose

John’s booster

20th November

So my protection against hospitalisation goes down from 92% to 83% by soon