By Gary Evans, Medical Writer
Even amid an ongoing storm of other respiratory infections, some argue that the widely predicted winter surge of COVID-19 in the United States will be blunted by vaccination, natural infection, and hybrid immunity in the population. There also are antiviral treatments and other options to prevent hospitalizations.
“We now have high rates of population immunity in the United States between vaccination, with 78% of those [older than] 18 [years of age] having had the primary series, and high rates of natural immunity,” says Monica Gandhi, MD, MPH, an infectious disease physician and director of the UC San Francisco-Bay Area Center for AIDS Research. “For instance, 86% of children in the United States [age 17 years and younger] have been infected with COVID-19, as evidenced by the presence of nucleocapsid antibodies to the virus, which reflect natural infection. Hybrid immunity, vaccination plus previous infection, is highly protective against subsequent infection as Omicron subvariants emerge.”
As of modeling reported on Oct. 24, 2022, the Institute for Health Metrics and Evaluation (IHME) at the University of Washington projected increased, milder cases of SARS-CoV-2, and less deaths than the winter of 2021-2022, reports IHME Director Christopher J.L. Murray, MD, DPhil.
“We continue to expect considerable increases in infections through the Northern Hemisphere winter, but without major increases in deaths due to COVID, but [still] quite a number of deaths with COVID, and the same for hospitalizations,” he said in a blog analysis.1
Milder cases bode well for the looming prospect of long COVID, but it still will be a formidable national and global challenge for some time to come.
“What we do know from the examination of the cohort studies is that [there] seems to be a higher risk of long COVID the more severe your case was, so much higher probabilities of long COVID if you went to the ICU (intensive care unit) or you were hospitalized than if you had mild symptoms,” Murray said.
Definitions vary for long COVID by time of duration, and the IHME reports cases of prolonged health effects after initial infection at three months out to 12 months and beyond.
“Some long COVID can be very long indeed,” Murray said. “The numbers, roughly speaking, are running about 6% of everyone [who has] COVID having symptoms at three months. And 1% have symptoms at the end of a year.”
Bivalent Vaccine Underused, Undervalued?
As for the new broadly recommended bivalent vaccine, Gandhi recommends it for older people and those who are immunocompromised. “Those who are still at risk of severe disease despite vaccination should receive the updated bivalent boosters,” she says.
This essentially is the argument vaccine expert Paul Offit, MD, made, saying data show the groups at risk are the people older than 65 years of age, those with serious medical conditions, and the immunocompromised. (See Hospital Infection Control & Prevention, November 2022.)
Staring straight in the face of a worse-case scenario — some new iteration of SARS-CoV-2 running rampant though a susceptible population — the Centers for Disease Control and Prevention (CDC) and the Food and Drug Administration (FDA) approved two bivalent vaccines containing the original SARS-CoV-2 Wuhan strain combined with the Omicron subvariants BA.5 and BA.4.
Looking at tens of thousands of deaths if immunity waned and the old vaccine did not work against the new variants, they moved ahead with a dearth of efficacy data, although the safety profile of the messenger ribonucleic acid (mRNA) vaccines now is well established. Pfizer’s bivalent booster was approved for those 5 years of age and older while the Moderna version is for those 12 years of age and older.
They cast a wide net, but it largely has come up empty. Only 12% of those 18 years of age and older have been immunized with the bivalent booster.
Those 65 years of age and older have been immunized at a 27% rate with the bivalent booster, which is concerning because their existing immunity is more likely to have waned than younger groups. Although most have had the two-shot initial series, 71% of those older than 65 years of age never received the subsequent boosters, which essentially were third and fourth shots of the original vaccines, Gandhi says.
“If we clarify the goals of our booster strategy to prevent severe disease, the annual booster campaign that the FDA has stated is the new strategy going forward will probably only be needed for people who are at highest risk (as defined by age, comorbidities, and whether they are immunocompromised),” she writes in a recently published commentary.2 “In fact, once a year might not be enough for some risk groups. We agree with the Canadian National Advisory Committee on Immunization to recommend the updated vaccine at an interval of six months after previous vaccination or infection. We are excited about the ability of the mRNA vaccines to be updated as new variants emerge. Focusing our booster recommendations on those most clinically vulnerable to severe disease first, and timing vaccine administration to optimize the immune response, is a good public health strategy.”
Pandemic Not Over
Although there is the scientific parsing of who really needs the new bivalent vaccine, Daniel Griffin, MD, a research scientist at Columbia University, takes a pragmatic perspective about pandemic coronavirus and vaccines.
“Never miss an opportunity to get vaccinated,” he said on a recent video broadcast.3 “Vaccinated people still get infections, they are just less likely to die or have severe disease.”
Surge or no surge, that seems like sage advice given this inconvenient truth: Contrary to widespread perception, the pandemic of highly mutable SARS-CoV-2 is not over.
Indeed, if this is endemic COVID-19, the annual toll will be steep. As of Nov. 12, 2022, the daily average of cases was 39,618, hospitalizations were at 28,039, and there were 317 deaths, according to The New York Times tracker. Concerning the mortality, it certainly is much lower than the earlier periods of thousands of deaths daily, but even 300 translates to more than 100,000 deaths per year. That is more mortality than really bad seasonal flu, such as the estimated 80,000 lives lost in the 2017-2018 season.
A recent study looking at hospitalized patients from January 2022 to April 2022 — when Omicron was the predominant variant — found “COVID-19-associated hospitalization rates were 10.5 times higher in unvaccinated persons.”4
Again, the new bivalent COVID-19 booster contains Omicron BA.5 and BA.4. As of Nov. 12, 2022, the Omicron subvariants were the dominating circulating virus, with BA.5 (30%), BQ.1.1 (24%), BQ.1 (20%), BF.7 (8%), and BF.4.6 (6%).5 The hope of public health officials in approving the bivalent booster was that it would cover other subvariants of Omicron as well.
RSV, Flu, COVID-19
The mitigation and masking measures for COVID-19 have decreased other respiratory viruses for a couple of years, but they appear to be back with vengeance.
“We suspect that many children are being exposed to some respiratory viruses now for the first time, having avoided these viruses during the height of the pandemic,” Jose Romero, MD, the director of CDC National Center for Immunization and Respiratory Diseases, said at a recent press briefing. “CDC has been tracking elevated levels of influenza, respiratory syncytial virus (RSV), rhinoviruses, and animal viruses.”
With influenza A being the primary circulating virus, the groups most at risk are the young and the elderly. “There are early signs of influenza causing severe illness in precisely these two groups this season with higher hospitalization rates reported,” he said. “In fact, we’re seeing the highest influenza hospitalization rates going back a decade. Sadly, this week, we are also reporting the second influenza-related pediatric deaths of this season.”
Diagnosis and treatment of RSV are well understood among healthcare providers, and most older children and adults recover within one to two weeks of infection. However, RSV can be serious, especially for infants and older adults,” Romero said. “It is the most common cause of bronchiolitis and pneumonia in children less than 1 year old.”
There is no vaccine for RSV, but those available for flu and COVID-19 are highly recommended, he said.
REFERENCES
- Murray CJL. New COVID-19 projections. Institute for Health Metrics and Evaluation. Published Oct. 24, 2022: https://www.healthdata.org/news-events/blogs/covid-19-insights-blog
- Doron S, Gandhi M. New boosters are here! Who should receive them and when? Lancet Infect Dis 2022; Oct 27:S1473-3099(22)00688-0. doi: 10.1016/S1473-3099(22)00688-0. [Online ahead of print].
- YouTube. TWiV 953: Clinical update with Dr. Daniel Griffin. Published Nov. 11, 2022. https://www.youtube.com/watch?v=Zcc0h7tNlhI&t=1262s
- Centers for Disease Control and Prevention. COVID Data Tracker. Variant proportions. Aug. 12, 2022. https://covid.cdc.gov/covid-data-tracker/#variant-proportions
- Havers FP, Pham H, Taylor CA et al. COVID-19-associated hospitalizations among vaccinated and unvaccinated adults 18 years or older in 13 US states, January 2021 to April 2022. JAMA Intern Med 2022;182:1071-1081.
Even amid an ongoing storm of other respiratory infections, some argue that the widely predicted winter surge of COVID-19 in the United States will be blunted by vaccination, natural infection, and hybrid immunity in the population.
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