Covid-19 Weekly Updates

First a personal thank-you message – I would like to express my appreciation to the College of Medicine in South Africa for conferring on me their highest honour – Honorary Fellowship in Virology. I did part of my specialist registrar (residency) training in Virology before it became an official medical specialty in South Africa and so, this recognition has a special meaning for me. 

 

Second, thanks for the many comments I received on the monkeypox email. I am sharing 2 comments here:

1. From Jeremy Farrar: 

- An interesting article on niches - Worth a quick read,

 

2. From Ali Zumla:

A Comment published in Lancet Infectious diseases on the current Monkeypox outbreak written by his PANDORA-Id-NET colleagues and himself sets out scientific and social priorities (Attached).  

 

The pandemic’s omicron wave continues to subside globally (Slides 16 and 18), despite increasing cases in some parts of the world due to omicron sub-variants eg. in North America (Slide 17). The case rates are still hovering around the low transmission level of 5 cases per 100,000 per day, which is good news. But, if past trends are anything to go by, this is likely to be the ebb before the next wave.

 

The BA.4 / BA.5 mini-wave is well and truly receding (slide 1), though hospitalisations are still high. Fortunately, deaths have not risen meaningfully (slide 13). It is apparent that both BA.4 and BA.5 have the potential to escape immunity and cause infection in those with past infection, including those who had BA.1 infection – and thereby lead to a new wave. But the low magnitude of the BA.4 / BA.5 wave (notwithstanding testing changes), suggests that it may not spread widely beyond the southern African region – well, let’s hope that this is the case.

 

Congratulations to Cheryl Cohen at the team at the NICD (South Africa’s CDC equivalent) for great data that sheds light on the community dynamics of repeated waves (slide 5). By following 1,200 people from 222 households longitudinally since the first wave, we now know that the first 3 waves (D614G, Beta and Delta) led to about 62% of the population becoming infected (88% detected by PCR) The blood bank released new data yesterday suggesting that almost every unvaccinated person has become infected with only 10% of the blood donor population protected by vaccination. Blood donors in South Africa are a highly skewed population and so their data do not represent the population of South Africa, but I suspect that it probably not too far the truth, as it is likely that somewhere between 80% and 90% of people in SA have been infected. So, SA could consider this an opportunity to try and get to a point where the 50% unvaccinated population get a single vaccine dose for hybrid immunity.

 

Another finding of the NICD study (slide 5) – it showed that 85% of those who got Covid-19 infection, were asymptomatic.  Reinfection occurred in 12% of the people; as prevalence of infected people goes up, this rate can be expected to increase markedly.

 

About reinfection, Katherine Wu of the Atlantic has written a superb article on reinfection (see attached and the link is), with an apt title: “You are going to get Covid again….And again…..And again”.