COVID-19 antibodies may linger for at least 7 months, study suggests
COVID-19 antibodies remained 7 months' post-infection, with some even increasing in levels, according to a follow-up study of 578 healthcare workers at the Hospital Clínic at Barcelona. The results, which were published today in Nature Communications, also include evidence that exposure to common cold coronaviruses may contribute to some cross protection.
The cohort submitted four different blood samples from March to October 2020, which were assessed for Immunoglobulin (Ig) A, IgM, and IgG antibodies to six different SARS-CoV-2 antigens as well as the presence of antibodies against four human coronaviruses (HCoVs). By month 6 post-symptom onset (PSO), 16.4% of the cohort had tested seropositive for COVID-19 at least once, and the researchers were able to look at kinetic curves based on samples from 76 symptomatic participants at a maximum of 7.7 PSO.
Overall, IgG levels were steady for spike protein (S) antigens and for IgA up to 230 days PSO, with 71% and 69% of participants remaining seropositive 6 months PSO, respectively. S-related IgG levels increased after 150 days in 73.9% of people, the researchers add, and plasma neutralizing capacity increased from symptom onset until day 80 but then remained stable up to 250 days PSO.
Comparatively, only 34% of participants were seropositive for IgM after 6 months, and even less (26%) were seropositive for nucleocapsid-related IgG. The researchers note that all IgA and IgM appeared to peak within the first month but then decline to 30% and 23.5% seropositivity at 1 and 3 months PSO.
"Importantly, we observed a trend towards higher levels of antibodies against HCoVs N proteins at baseline in those participants who did not become infected with SARS-CoV-2, suggesting some level of cross-protection against infection," the researchers write. Furthermore, data showed that asymptomatic COVID-19 patients had higher anti-HCoV IgG and IgA levels.
"Although cross-protection by pre-existing immunity to common cold coronaviruses remains to be confirmed, this could help explain the big differences in susceptibility to the disease within the population," said study lead Carlota Dobaño, PhD, in a Barcelona Institute for Global Health (ISIGlobal) press release.
Aug 6 Nat Comm study
Aug 6 ISI Global press release
Long COVID-19 in hospitalized patients affected mental, physical health
Lingering symptoms affected most COVID-hospitalized patients mentally or physically 6 months post-discharge, according to a study yesterday in the Journal of General Internal Medicine.
The researchers surveyed 126 people who completed a 1-month and 6-month survey after being discharged from a New York University hospital from Apr 15 to May 30, 2020. All had needed at least some supplemental oxygen, and most (60%) were male, with the median age of 62 years. Almost three out of four people (74%) were still experiencing worse health compared with baseline functions and reported an average of 7.1 symptoms. Furthermore, some had even required an emergency department visit (15%) or hospital readmission (8%).
Compared with their average summary scores via the 100-point PROMIS Global Health-10 instrument, overall physical health was still worse (45.2 vs 53.7 pre-COVID) as was mental health (47.4 vs 54.2). Shortness of breath affected 63% of the cohort, and 9% of 124 patients without pre-COVID oxygen requirements still needed supplemental oxygen post-discharge. Those who had needed intensive care unit (ICU) treatment were more likely to report lingering health issues, but PROMIS Global Health-10 outcomes and shortness of breath measurements were still similar to the overall group.
Fatigue (85%), muscle weakness (46%), memory difficulties (41%), and brain fog (37%) were also commonly reported.
"In conclusion, we found that patients discharged after hospitalization for severe COVID-19 still experience symptoms that may affect their quality of life even 6 months after discharge. Support and treatment are needed to return these patients back to their pre-COVID baseline," write the researchers.
Aug 5 J Gen Int Med study