Confirmed cases in Easthampton are about the same last week as the week before. The 7-day average of new cases per day is slightly down from the prior week, while the 14-day average is slightly up. The percent positivity is up again, however, and really getting quite close to 5%. Hitting 5% would put us in that old "red" zone of transmission, which we have maintained for comparison purposes and because it gives us a fairly good sense of community transmission.
Hampshire County is in the "medium" category of transmission again, according to the CDC. This categorization, again, is more focused on severe disease and the capacity of the healthcare system to handle a surge, rather than just on cases. Unfortunately, hospitalizations are continuing to slowly increase in Massachusetts and in Western Mass. There are still few patients in the ICU right now. The concern is that hospitalizations and especially ICU admissions are a lagging indicator, and won't rise until at least two weeks after an increase in cases. To see that rising (even slowly, still!) while cases are still rising is a little concerning. Other local counties have been upgraded to this medium risk category, and counties in New York, Vermont, New Hampshire, and Maine have been upgraded to high risk.
The CDCs official recommendation for folks in Hampshire County (in the medium risk category) is to contact your healthcare provider to determine if you should wear a mask indoors. The general advice from experts in the public health community are that those who are high-risk, immunocompromised, unvaccinated (including children under 5 who can't be vaccinated yet), or who live with someone who fits that description should be masking indoors at this point. I concur. Remember, a KF94 / KN95 / N95 mask will provide you with an excellent level of protection.
It's not all grim! The good news is that the concentration of SARS-CoV-2 viral particles in wastewater seems to have plateaued in the past week. One week is not enough to determine a trend, but I am encouraged both by the plateau itself and the fact that viral particle concentration hasn't shot upwards (like it did during the winter omicron variant surge). The wastewater surveillance data indicates that almost 90% of the viral particles identified in the past week are the BA.2 variant.
All eyes are again on South Africa, because they're headed into another surge of cases and hospitalizations as the omicron subvariants BA.4 and BA.5 become dominant there. For those keeping track at home, here's a brief overview of the omicron variants timeline in South Africa (and then I'll say what that might mean):
1) BA.1 (omicron) was identified in South Africa in November and quickly became dominant and caused a massive surge in cases.
2) BA.2 became the dominant variant in South Africa in February, and there was no associated surge in cases.
3) BA.4 and BA.5 are now widely circulating in South Africa and there is an associated surge in cases.
What does this all mean? There's a lot we don't know, but there are a few things that are concerning about BA.4 and BA.5. In order for a new variant / sub-variant to become dominant, it has to be more transmissible than the currently dominant variant. It has to - if not, it won't outcompete the current variant. Lots and lots of mutations fade this way and don't even rise to the level of being a "variant." So, adding that information in -
1) BA.1 is much more transmissible than the delta variant.
2) BA.2 is more transmissible than BA.1.
3) BA.4 and BA.5 are more transmissible than BA.2
The big question, however, is if a new variant evades immunity. Specifically, will folks with prior immunity be protected from infection or severe disease? Even a highly transmissible variant isn't going to cause much difference in case counts if most people have some kind of immunity (natural or vaccine). But if there's a new, highly transmissible variant that even folks with immunity are not actually all that immune to - well, that might cause a surge in cases. Waning immunity plays a role as well, of course - South Africa is 3+ months out from their omicron surge. Lab data on antibody protection against BA.4 and BA.5 suggests that there is significant immune evasion against immunity from prior infection. So, putting it all together -
1) BA.1 is much more transmissible than the delta variant and had considerable immune evasion --> big surge in South Africa
2) BA.2 is more transmissible than BA.1 but did not seem to evade immunity --> no surge in South Africa
3) BA.4 and BA.5 are more transmissible than BA.2, both evade immunity (especially natural immunity) and South Africa is 3+ months out from the BA.1 surge --> cases are increasing in South Africa
TL;DR (too long; didn't read): BA.4 and BA.5 are dominant in South Africa and are both more transmissible than prior variants. They evade prior immunity, especially natural immunity, and are causing a surge in cases. Will one "win out" over the other? Will there be a small / medium / big surge in cases in the US? It’s difficult to predict what the surge in South Africa means for other countries. Local case activity depends on many things, like local vaccination rates, prior infections (and timing of vaccines and infections), virus restrictions, and probably even things like weather / time of year.
A note on the concept of "immune evasion" - this doesn't mean that prior infection or vaccine provides NO protection, it just means that the level of protection against infection is lower than it was before, against other variants. Prior vaccine immunity plays an enormous documented role in protecting people from infection and especially severe disease, even during surges of variants with immune evasion.
Back to the US / Northeast:
BA.2 is dominant in the US and in the Northeast. We are also dealing with the BA.2.12.1 sub-sub-variant - I don't see data available at that level of sequencing in Hampshire County, though. The current proportion of each variant in the US is seen in the graph from the CDC. The situation in the US is not a perfect parallel for the situation in South Africa, including that we're already experiencing a small increase in cases associated with the BA.2 variant. So what will happen when BA.4 and/or BA.5 become dominant? Time will tell. Vaccines remain incredibly protective against severe disease, and are your best personal layer of protection. Case rates still matter though - to keep vulnerable populations protected and to not break the healthcare system.
Pediatric Vaccine Update:
Moderna announced that it will have all data on the under 5 vaccine submitted to the FDA for emergency use approval by Monday, May 9th. The vaccine is a tw-dose series 1/4th of the strength of the adult Moderna dose. The FDA has set a tentative day to review the data of Tuesday, June 8th - a delay of about 30 days. This is certainly not a date that means the FDA is waiting to review the Pfizer and Moderna vaccines together, but there is no clear reason why the meeting isn't going to occur for another month. No explanation has been provided, and experts are challenging the decision. For comparison, here are the number of days between a complete submission and FDA EUA review for other vaccines:
- Moderna 18+ vaccine: 17 days
- Pfizer 16+ vaccine: 20 days
- Pfizer 12-15 vaccine: about 15 days
- Pfizer 5-11 vaccine: 19 days
Data on the Pfizer pediatric vaccine is expected sometime in June, and if the 20-30 day wait between submission and review holds, will be available likely in July. The Pfizer vaccine is a series of 3 doses, each 1/10th of the strength of the adult dose.
Take good care out there, Easthampton.
Megan W. Harvey, PhD (she/her)Epidemiologist