Just 1 vaccine dose may protect recovered COVID patients from new infection
Recovered COVID-19 patients given a single dose of a currently authorized mRNA vaccine had a robust immune response equal to or exceeding that reached by their coronavirus-naïve peers after the second dose, according to a non–peer reviewed study published yesterday on the medRxiv preprint server.
Currently, the recommended dosing schedule for the two authorized mRNA vaccines, manufactured by Pfizer/BioNTech and Moderna, is two doses given 3 or 4 weeks apart. But the study researchers at Mount Sinai’s Icahn School of Medicine say their findings suggest that the current policy could be amended to include only one dose in recovered coronavirus patients, sparing them from side effects and freeing up urgently needed doses.
Of the 68 coronavirus-naïve vaccine recipients given the first dose, 51 had mixed, relatively low immune responses by 9 to 12 days after vaccination. In contrast, within days of vaccination, all 41 vaccinees with antibody evidence of previous COVID-19 infection mounted antibody responses 10 to 20 times higher than did vaccinees who were seronegative, or had no coronavirus antibodies. In fact, their antibody levels, or titers, were 10 times higher than those in seronegative vaccinees after they received the second dose.
While seronegative vaccine recipients experienced only mild side effects after the first dose, the most common of which were pain, swelling, and redness at the injection site, seropositive vaccine recipients had significantly more side effects, including fatigue, headache, chills, fever, and muscle or joint pain.
“These observations are in line with the first vaccine dose serving as boost in naturally infected individuals, providing a rationale for updating vaccine recommendations to considering a single vaccine dose to be sufficient to reach immunity,” the authors said.
They suggested using serological tests to measure antibody levels to the coronavirus spike protein to screen vaccine candidates before vaccination if they don’t know whether they’ve had COVID-19. “Such policies would allow not only expanding limited vaccine supply but also limit the reactogenicity experienced by COVID-19 survivors,” the researchers concluded. “Ongoing follow-up studies will show whether these early differences in immune responses are maintained over time.”
Feb 1 medRxiv study
Extracorporeal membrane oxygenation may help with severe COVID-19
Intensive care unit (ICU) patients with severe COVID-19 who received extracorporeal membrane oxygenation (ECMO) within the first 7 days had a mortality rate of 34.6%, 12.8 percentage points lower than those who didn’t, according to a study today in Intensive Care Medicine. ECMO exchanges carbon dioxide for oxygen in the blood outside the body and is given to those with severe respiratory failure.
The primary results showed that 130 patients treated with ECMO had an adjusted hazard ratio of 0.55 compared with the 1,297 who were not (95% confidence interval, 0.41 to 0.74), meaning a 45% lower death rate.
Using a target trial emulation approach, which is meant to act as a pseudo randomized, controlled trial, the researchers pulled data from 55 hospital ICUs with ECMO capabilities across the United States from Mar 1 to Jul 1, 2020. In the original data pool, 190 of 5,122 patients (3.7%) received ECMO. After 60 days, most of those who received ECMO were still alive, either discharged (49.5%) or still hospitalized (17.4%).
Patients who received ECMO were started on it a median of 3 days after ICU admission. The most frequent complications from ECMO were bacterial pneumonia (34.7%), bleeding (27.9%), thrombotic events (22.9%), and acute kidney injury that needed renal replacement therapy, which can include dialysis (21.8%).
“ECMO gives patients’ lungs time to heal when we’ve exhausted every other aspect of care for these patients—it can be a bridge to recovery,” said Shahzad Shaefi, MD, corresponding author, in a Beth Israel Deaconess Medical Center (BIDMC) press release. “But ECMO’s efficacy in the context of COVID-19 remains unclear. This work sheds new light on that question in the most robust way possible during the COVID-19 pandemic.”
Feb 2 Intensive Care Med study
Feb 2 BIDMC press release
Study: COVID-19 ICU death rates fell steadily but may have plateaued
Mortality rates in intensive care units (ICUs) have dropped globally since the start of the pandemic, but the reduction is slow and may be plateauing, according to a study yesterday in Anaesthesia.
Previous analyses showed ICU mortality rates fell by one-third from 60% at the end of March to 42% at the end of May in 2020. In this new study, which included data through October 2020, ICU mortality rates fell to 36%.
The authors based their study on 52 observational studies, which included more than 43,000 patients in Europe, North America, China, South Asia, the Middle East, and Australia.
The Middle East and Australia represented the two outliers: Regions of Australia boasted an ICU mortality rate of 11%, while the rate in certain parts of the Middle East rose above 62%. In most geographic regions, though, ICU COVID-19 mortality has remained between 30% and 40% throughout 2020.
“After our first meta-analysis last year showed a large drop in ICU mortality from COVID-19 from March to May 2020, this updated analysis shows that any fall in mortality rate between June and October 2020 appears to have flattened or plateaued,” the authors concluded in a news release from the Association of Anaesthetists (in full the Association of Anaesthetists of Great Britain and Ireland [AAGBI]).
The authors also noted that ICU mortality rates would likely change again, both as new, more contagious variants of the virus circulate, and more people receive vaccination against the coronavirus.
Feb 1 Anaesthesia study
Feb 1 AAGBI news release
Sweden reports lower COVID-19 ICU rates than rest of Europe
Mortality rates in Swedish intensive care units (ICUs) were lower during the first wave of the COVID-19 pandemic compared with other European countries, according to a new study in the European Journal of Anaesthesiology.
As in other countries, mortality in Sweden from COVID-19 was driven by several predictable factors: age, severity of disease, and the presence of organ failure. But unlike other countries, Sweden did not commit to a society-wide lockdown during the first wave of the pandemic.
“Coupled with what is widely perceived to be a ‘relaxed’ national pandemic strategy, results for ICU care in Sweden are understandably under scrutiny,” the authors said in a European Society of Anaesthesiology and Intensive Care (ESAIC) press release.
The data comes from 1,563 adult admissions to Swedish ICUs from Mar 6 to May 6, 2020. Thirty-day all-cause mortality was 27%, and mortality within the ICUs was 23%. Chronic lung disease was the only comorbidity to be associated with increased mortality, and it carried a 50% increased risk of death.
Other European countries with data from roughly the same period show higher rates of ICU mortality, with Italy reporting the highest rate, at 49%. A French-Belgian-Swiss study showed ICU mortality rates from 26% to 30%, and various North America studies show a 35% mortality rate in ICUs during the first pandemic wave.
“We believe that process and organisational factors have likely contributed to the relatively good outcomes seen in Swedish ICUs as staffing, protective equipment, availability of drugs, medical and technical equipment were considered at an early stage at hospital and regional levels,” the authors concluded in the press release.
Jan 28 Eur J Anesthesiol study
Feb 1 ESAIC press release