Virus World

BUENOS AIRES — President Alberto Fernández of Argentina tested positive for Covid-19 on Saturday and was experiencing mild symptoms despite having been vaccinated earlier this year, becoming the latest in a series of world leaders who have contracted the virus. In a series of tweets sent early Saturday, Mr. Fernández said a “light headache” and a temperature of 99.1 degrees had prompted him to take a quick antigen test. Its positive finding was confirmed later Saturday by a more rigorous P.C.R. test, said Dr. Federico Saavedra, the president’s physician. Mr. Fernández’s symptoms were “mild due in large part to the protective effect of the vaccine,” Dr. Saavedra said. The president, who first learned the preliminary result on Friday, his 62nd birthday, said he would remain in isolation. “I am physically well, and although I would have liked to end my birthday without this news, I’m also in good spirits,” the president wrote on Twitter. Mr. Fernández joins a list of world leaders who have contracted the virus, including Andrés Manuel López Obrador of Mexico, Jair Bolsonaro of Brazil, Emmanuel Macron of France and Donald Trump of the United States, during the final months of his presidency. But Mr. Fernández appears to be the first of those leaders to test positive for Covid-19 after having been fully vaccinated. He received the first dose of Russia’s Sputnik V vaccine on Jan. 21 and the second dose on Feb. 11.

BACKGROUND

Convalescent plasma is frequently administered to patients with Covid-19 and has been reported, largely on the basis of observational data, to improve clinical outcomes. Minimal data are available from adequately powered randomized, controlled trials.

METHODS

We randomly assigned hospitalized adult patients with severe Covid-19 pneumonia in a 2:1 ratio to receive convalescent plasma or placebo. The primary outcome was the patient’s clinical status 30 days after the intervention, as measured on a six-point ordinal scale ranging from total recovery to death.

RESULTS

A total of 228 patients were assigned to receive convalescent plasma and 105 to receive placebo. The median time from the onset of symptoms to enrollment in the trial was 8 days (interquartile range, 5 to 10), and hypoxemia was the most frequent severity criterion for enrollment. The infused convalescent plasma had a median titer of 1:3200 of total SARS-CoV-2 antibodies (interquartile range, 1:800 to 1:3200]. No patients were lost to follow-up. At day 30 day, no significant difference was noted between the convalescent plasma group and the placebo group in the distribution of clinical outcomes according to the ordinal scale (odds ratio, 0.83 (95% confidence interval [CI], 0.52 to 1.35; P=0.46). Overall mortality was 10.96% in the convalescent plasma group and 11.43% in the placebo group, for a risk difference of −0.46 percentage points (95% CI, −7.8 to 6.8). Total SARS-CoV-2 antibody titers tended to be higher in the convalescent plasma group at day 2 after the intervention. Adverse events and serious adverse events were similar in the two groups.

CONCLUSIONS

No significant differences were observed in clinical status or overall mortality between patients treated with convalescent plasma and those who received placebo. (PlasmAr ClinicalTrials.gov number, NCT04383535. opens in new tab.)

Published in NEJM (November 24, 2020):

https://doi.org/10.1056/NEJMoa2031304

A clinical trial in older adults with COVID-19 shows that an early dose of blood plasma from recovered people helps to prevent the progression to severe disease. The plasma of people who have recovered from COVID-19 contains antibodies against SARS-CoV-2. But treatment with such plasma has had mixed results, and some scientists have suggested that plasma needs to be given early in the disease course to be effective. Fernando Polack at Fundación INFANT in Buenos Aires and his colleagues conducted a rigorous clinical trial to assess the effect of treatment with plasma within 72 hours of symptom onset. Participants included people over the age of 75 and those between 65 and 74 with at least one pre-existing condition such as diabetes (R. Libster et al. N. Engl. J. Med. https://doi.org/10.1056/NEJMoa2033700; 2021). Severe COVID-19 developed in 16% of the 80 study participants who received plasma and 31% of the 80 participants in the placebo group. The team found that donor plasma containing higher concentrations of antibodies against SARS-CoV-2 was associated with a greater reduction in the risk of developing severe disease — providing evidence that the antibodies themselves are responsible for the therapeutic effect.