Yesterday the CDC published their latest COVID Nowcast which shows - as expected - the continued shift away from the XBB variants that held sway last May when the fall COVID vaccine was created, and towards an antigenically shifted BA.2.86 and its offshoots HV.1, JN.1 and HK.3.
While BA.2.86 hasn't spread quite as rapidly as some initially feared - based on limited surveillance and testing data - it appears to be gaining ground in many places around the globe. Yesterday the CDC published a separate update yesterday on its progress (see excerpt below).
Update on SARS-CoV-2 Variant BA.2.86 Being Tracked by CDC
November 27, 2023, 1:15 PM EDT
CDC is tracking a SARS-CoV-2 variant called BA.2.86 and working to better understand its potential impact on public health.This update follows CDC’s most recent BA.2.86 update on September 15, 2023.
Find more information about virus trends in your area and tips to help you stay healthy during the holidays.
What to know about BA.2.86
- The virus that causes COVID-19 is constantly changing over time. Sometimes these changes allow new variants to spread more quickly or effectively. If that occurs, the new variant may become more common relative to other variants that are circulating.
- Since CDC’s first post on BA.2.86 in August 2023, the proportion of infections caused by BA.2.86 has slowly increased. In the CDC Nowcast posted Nov. 27, 2023, BA.2.86 is projected to account for 5-15% of currently circulating variants.
- CDC projects BA.2.86 and its offshoots like JN.1 will continue to increase as a proportion of SARS-CoV-2 genomic sequences.
- At this time, BA.2.86 does not appear to be driving increases in infections or hospitalizations in the United States.
- CDC contributed to and agrees with the World Health Organization’s recent risk assessment about BA.2.86 suggesting that the public health risk posed by this variant is low compared with other circulating variants, based on available limited evidence.
- Updated COVID-19 vaccines are expected to increase protection against BA.2.86, as they do for other variants.
- As mentioned in previous updates, COVID-19 tests and treatments are expected to be effective against this variant, including its offshoot JN.1.
- It is not possible at this time to know whether BA.2.86 infection produces different symptoms from other variants. In general, symptoms of COVID-19 tend to be similar across variants. The types of symptoms and how severe they are usually depend more on a person’s immunity than which variant causes the infection.
- Regardless of what variants happen, CDC will continue to track them, working closely with partners around the world to understand how they are spreading and how they respond to vaccines and treatments.
Although we've seen vague assurances that `Updated COVID-19 vaccines are expected to increase protection against BA.2.86', today we've a preprint that better quantifies those expectations, finding this updated vaccine elicits `robust neutralizing antibodies' against these newer variants.
While not a precise gauge of a vaccine's effectiveness, studies have shown that higher neutralizing antibody titres are strongly correlated with observed vaccine effectiveness (VE) against symptomatic and/or severe COVID infection.
Like the CDC update above, this preprint also discusses the growth advantage of the BA.2.86 variant and its offshoots, and expects them to eventually supplant XBB.1.5 and EG.5.1. I've only posted some excerpts, so follow the link to read it in its entirety.
I'll have a bit more after the break.
Qian Wang, Yicheng Guo, Anthony Bowen, Ian A. Mellis, Riccardo Valdez, Carmen Gherasim, Aubree Gordon, Lihong Liu, David D Ho
doi: https://doi.org/10.1101/2023.11.26.568730
Abstract
COVID-19 vaccines have recently been updated with the spike protein of SARS-Co-V-2 XBB.1.5 subvariant alone, but their immunogenicity in humans has yet to be fully evaluated and reported, particularly against emergent viruses that are rapidly expanding.
We now report that administration of an updated monovalent mRNA vaccine (XBB.1.5 MV) to uninfected individuals boosted serum virus-neutralization antibodies significantly against not only XBB.1.5 (27.0-fold) and the currently dominant EG.5.1 (27.6-fold) but also key emergent viruses like HV.1, HK.3, JD.1.1, and JN.1 (13.3-to-27.4-fold).
In individuals previously infected by an Omicron subvariant, serum neutralizing titers were boosted to highest levels (1,764-to-22,978) against all viral variants tested. While immunological imprinting was still evident with the updated vaccines, it was not nearly as severe as the previously authorized bivalent BA.5 vaccine. Our findings strongly support the official recommendation to widely apply the updated COVID-19 vaccines to further protect the public.
(SNIP)
Our results also showed that HV.1, HK.3, and JD.1.1 are more resistant to serum neutralization than XBB.15 by about 1.6-to-2.5-fold (Figures 2b-2d), a finding that suggests that these emergent subvariants are likely to have a growth advantage in the population over their immediate precursors. If so, we can expect these new sublineages to replace XBB.1.5 and EG.5.1.Likewise, JN.1 is even more antibody resistant, by 2.9-to-4.3-fold, to the serum samples tested here (Figure 3). Widespread application of the updated XBB.1.5 monovalent vaccines could confer an even larger growth advantage in the population to JN.1 as well as to the related BA.2.86, thereby posing a potential threat to the newly authorized COVID-19 vaccines.While immunological imprinting is evident with the XBB.1.5 monovalent mRNA vaccines studied, as discussed above, it is not nearly as severe as those observed for the BA.5 bivalent vaccines (Figure 4). One potential explanation is that XBB.1.5 is genetically and antigenically more distant from the ancestral SARS-CoV-2 than BA.5, which might mitigate immunological imprinting to an extent. Perhaps a more likely explanation is the non-inclusion of the ancestral spike in the current XBB.1.5 monovalent vaccines.
Previous studies on the bivalent WA1+BA5 vaccines by our team14-17 and others18 suggested that the inclusion of the ancestral spike exacerbated the problem of imprinting and recommended its removal. Our findings herein indicate that WHO, FDA, and the vaccine manufacturers made the right choice by formulating the new COVID-19 vaccines based on XBB.1.5 spike alone, without including the ancestral spike.This study is limited to evaluation of serum neutralizing antibodies, without addressing T-cell responses19-21 or mucosal immunity22-24, both of which could provide added protection against SARS-CoV-2. Moreover, we have only examined acute antibody responses after XBB.1.5 monovalent vaccine booster or XBB.1.5 infection, but how such responses evolve over time will require follow-up studies. These limitations notwithstanding, our results not only demonstrate that administration of an XBB.1.5 monovalent mRNA vaccine booster can elicit robust neutralizing antibodies against current and emerging SARS-CoV-2 variants, but also support FDA’s recommendation to apply these updated COVID-19 vaccines more widely to confer greater protection to the public.
Flu Vaccination Among Children
As of November 4, 2023, flu vaccination coverage among children overall is about 4 percentage points lower than the same time last season. Coverage among White and Black children is down by about 7 and 6 percentage points respectively. While flu vaccination coverage among children increased the two seasons prior to the COVID-19 pandemic (2018–2020), coverage declined during the pandemic and at 57% at the end of last season, was about 6 percentage points below pre-pandemic levels.
Flu Vaccination Among Adults
Flu vaccination coverage for adults 18 years and older as of October 14, 2023, was about 3 percentage points lower overall than the same time last season. At that time, racial disparities persisted with coverage among White adults being about 11 percentage points higher than among Black adults. Flu vaccination coverage among pregnant people as of October 31, 2023, was similar to the same time last season. Different CDC data sources estimate that at the end of last season, flu vaccine coverage among pregnant women since the COVID-19 pandemic was in the range of 10 to 15 percentage points.
I admittedly have modest expectations for the amount of protection provided by the flu and COVID vaccines, but I'm grateful for whatever benefits they can provide. Even if they don't always prevent breakthrough infection, they can often reduce the severity of that illness.
And there is evidence that flu vaccines may reduce the risks of heart attacks, strokes, and even neurological disorders (see Nature: Influenza Vaccination & Major Cardiovascular Risk: a Systematic Review & Meta-Analysis).
Sadly, between incessant and highly misleading vaccine information on social media - and inevitable pandemic fatigue after 4 frustrating years of COVID - it is getting harder to convince the public to roll up their sleeves for seasonal and routine vaccinations.
While that trend no doubt costs lives now, entrenched vaccine hesitancy could prove even more damaging should we find ourselves faced with another pandemic threat anytime soon.
And given the number of threats out there, that could come a lot sooner than most people think.
