The official case rate and percent positivity increased last week, although the wastewater surveillance data doesn't show any increase in viral concentration. I'm not sure what that's about - most likely it means nothing, and the numbers are within the range of variance in testing and reporting. If it does have further meaning, it will take us a few weeks to see that. Hospitalizations are down in Hampshire County, moving us back into the low risk category. All in all, I'm counting last week as a continuation of good news.
I'm continuing to puzzle over the difference in variant tracking from the Centers for Disease Control and Biobot Analytics. According to the CDC, XBB 1.5 is completely dominant in the Northeast, accounting for nearly 90% of infections. BioBot Analytics provides an estimate of the variant proportions within wastewater in Hampshire County, and last week XBB 1.5 accounted for only about 25% of infections. BioBot's estimate of the Northeast in general is that XBB 1.5 accounts for about 60% of infections. I looked through other counties in MA, and BioBot estimates that XBB 1.5 accounts for an average of 70-80% of infections. I don't know what to make of this! It might mean nothing, but I'll continue to monitor it.
There were two key meetings to report on this week:
1) The World Health Organization's International Health Regulations Emergency Committee met and announced that their panel of experts have determined that the COVID-19 pandemic is still a global health emergency. This distinction is important because it provides health officials the ability to provide support for vaccination and treatment efforts broadly (and internationally). Director General Tedros announced that the committee acknowledged general improvement in the global situation and that they believe the pandemic crisis is at an "inflection point" where increasing levels of immunity may soon lead to lower COVID-19 related deaths. The committee will meet again in three months.
2) The VRBPAC (Vaccines and Related Biological Products Advisory Committee) met last week to discuss the national plan for COVID-19 boosters moving forward. Specifically, they discussed a proposal to move to an annual COVID-19 booster available each fall, just as is done with the annual influenza vaccine. The goal of the proposal is to move to a proactive, sustainable, and effective approach to maintaining high population immunity (in other words - how to get people to actually get new COVID-19 boosters when they become available). The short version of the update is that although it's not universally agreed upon, it sounds like this is the direction the CDC/FDA will go. A few important things were discussed during the meeting:
- The VRBPAC has good reason to be concerned with vaccine uptake moving forward - the proportion of those in the US who have received the bivalent booster is alarmingly small. It's relatively high in Massachusetts, but Massachusetts is one of a few states with high bivalent booster uptake. Being on the higher end of vaccine uptake isn't saying much, however, when we're talking about only about 30% of the eligible population getting the booster (the rate is about double that among those ages 75 and over, though). The bottom line is that there is plenty of work to do to move towards most people being "up-to-date" on the COVID-19 vaccine, even in a highly vaccinated state like Massachusetts.
- The VRBPAC presented more data on the effectiveness of the bivalent booster. The data on safety and effectiveness remains clear: there are no "safety signals" (that's CDC speak for "things to worry about") and the vaccine provides a high level of protection against infection and severe disease. The risk of death is much lower among those who are vaccinated, compared to those who are unvaccinated. And those who have the updated bivalent booster have about half the risk of death of those vaccinated without the bivalent booster. That's a significant difference, statistically and practically!
- Another important aspect of the VRBPAC discussion centered around ongoing risk from COVID-19. They presented data on hospitalizations by age group. The group with the greatest risk of hospitalization is those over age 75 years old, and those age 65-74. This has been widely acknowledged. However, we have focused less on another important group at high risk: infants under 6 months old. Infants under 6 months have the 3rd highest risk of hospitalization, just a tiny bit less than those ages 65-74. Risk drops off dramatically after 6 months - interestingly, the first age of eligibility for the COVID-19 booster. (That was an epidemiology joke - it's not "interesting", it's quite predictable!) This highlights the ongoing risk of COVID-19 among unvaccinated and high-risk populations, and emphasizes the importance of maintaining boosters in eligible groups and vaccinating pregnant women to protect infants.
That seems like more than enough for this week. :)