Enlarge / A phlebotomist draws blood meant for antibody testing. (credit: Frederic J. Brown / Getty Images )

We've tended to treat the RNA-based vaccines from Moderna and Pfizer/BioNTech as functionally equivalent. They take an identical approach to producing immunity and have a very similar set of ingredients. Clinical trial data suggested they had very similar efficacy—both in the area of 95 percent.

So it was a bit of a surprise to have a paper released yesterday indicating that the two produce an antibody response that's easy to distinguish, with Moderna inducing antibody levels that were more than double that seen among people who received the Pfizer/BioNTech shot. While it's important not to infer too much from a single study, this one was large enough that the results are likely to be reliable. If so, the results serve as a caution that we might not want to base too many of our expectations on relatively crude measures of antibody levels.

The new study

The work itself was remarkably simple. A Belgian medical center was vaccinating its staff and asked for volunteers willing to give blood samples. Samples were taken both prior to vaccination and six to 10 weeks after, with the levels of antibody specific to the SARS-CoV-2 spike protein tested at both points. About 700 participants received the Moderna vaccine, while roughly 950 took the one from Pfizer/BioNTech.

Enlarge / The structure of the SARS-CoV-2 spike protein. (credit: University of Arkansas )

Over the summer, you could almost hear a sigh of relief rising from the portion of the research community that was tracking the evolution of the SARS-CoV-2 virus. Viruses, especially those new to their hosts, often pick up mutations that help them adapt to their new habitat, or they evade drugs or immune attacks. But SARS-CoV-2 seemed to be picking up mutations at a relatively sedate pace, in part because its virus-copying enzymes had a feature that lets them correct some errors.

But suddenly, new variants appear to be everywhere , and a number of them appear to increase the threat posed by the virus. A new study helps explain the apparent difference: while new base changes in the virus' genetic material remain rare, some deletions of several bases appear to have evolved multiple times, indicating that evolution was selecting for them. The research team behind this new work found evidence that these changes alter how the immune system can respond to the virus.

This looks familiar

The researchers' interest in deletions started with their involvement with an immunocompromised cancer patient, who held off the infection for over two months without being able to clear the virus. Samples obtained from late in the infection revealed two different virus strains that each had a deletion in the gene encoding the spike protein that SARS-CoV-2 uses to attach to and enter cells.

Enlarge (credit: CDC.gov )

As the world races to get vaccines into arms, one of the most concerning coronavirus variants appears to be getting a little more concerning.

Researchers in the UK have detected at least 15 cases of B.1.1.7 variants carrying an additional mutation: E484K—a mutation already seen in other concerning variants , and one that may make current vaccines less effective at preventing infection. The B.1.1.7 variant, first identified in the United Kingdom, is already known to spread more easily among people than earlier strains of the pandemic coronavirus SARS-CoV-2. And according to some preliminary evidence, it may cause more severe disease.

So far, B.1.1.7 variants carrying E484K appear rare. On Monday, Public Health England reported in a technical briefing that it had detected E484K in just 11 B.1.1.7 variants among more than 200,000 viruses examined. For now, it’s unclear if the augmented mutants will take off and become dominant in the population or fizzle out. It’s also not entirely clear what the addition of E484K means for B.1.1.7 in people. Preliminary laboratory experiments suggest the mutation alone and its presence in B.1.1.7 specifically may help the virus evade immune responses. But more studies and clinical data are necessary to understand the full effect of the new addition.

Enlarge / Staff from South Sudan's Health Ministry pose with protective suits during a drill for Ebola preparedness conducted by the World Health Organization (WHO). (credit: Getty | Patrick Meinhardt )

The Food and Drug Administration on Tuesday issued the first-ever approval for a therapy against Ebola virus disease .

Though the Ebola vaccine, Ervebo, earned approval late last year and proved 97.5 percent effective in preliminary trials, the newly approved therapy may be useful in addressing an ongoing outbreak in Democratic Republic of Congo, which began in June. The FDA’s approval may also boost the outlook for similar therapies being developed for COVID-19, which may become available before a vaccine.

The newly approved Ebola treatment, called Inmazeb (aka REGN-EB3), is a combination of three monoclonal antibodies made by Regeneron Pharmaceuticals. The antibodies target the only protein on the outside of Ebola virus particles, the glycoprotein. Ebola uses its glycoprotein to attach to and enter human cells, sparking infection. The cocktail of antibodies glom on to the protein, keeping it from invading cells.

Enlarge / FDA Commissioner Stephen Hahn, speaking at the press conference in which he badly mangled statistics. (credit: Pete Marovich/Getty Image )

After several days of rumors with ever-growing hype, the Trump administration announced on Sunday that the Food and Drug Administration was granting an Emergency Use Authorization (EUA) for a COVID-19 treatment. The move was controversial from the start, with reports indicating that the EUA was opposed by a number of health experts, including Francis Collins and Anthony Fauci. The press conference didn't settle matters, with a growing chorus of scientists saying that the data presented in support of the EUA had been misrepresented .

On Monday night, FDA commissioner Stephen Hahn acknowledged that he had made a significant error in presenting the benefits of the treatment, and he followed that with an apology on Tuesday . But Hahn pushed back on indications that the approval of the treatment on the eve of the Republican National Convention was motivated by political pressure.

Wrong kind of risk

The treatment at issue involves taking the antibody-containing plasma from those who have recovered from a SARS-CoV-2 infection (convalescent plasma) and giving it to those currently suffering from COVID-19 symptoms. At Sunday's press conference, the principle justification for allowing this treatment under an EUA was a 35 percent drop in mortality for those receiving plasma in the first three days of treatment—specifically, Hahn said 35 of 100 people "would have been saved" by this treatment.

Enlarge / Medical staff wearing personal protective equipment (PPE) as a precautionary measure against the COVID-19 coronavirus approach Lei Muk Shue care home in Hong Kong on August 23, 2020. (credit: Getty | May James )

A healthy, 33-year-old man in Hong Kong is now the first person in the world confirmed to have been reinfected by the pandemic coronavirus, SARS-CoV-2—which has currently infected more than 23 million people worldwide.

The man’s first infection was in late March. He reported having a cough with sputum, fever, sore throat, and a headache for three days before testing positive for the virus on March 26. Though his symptoms subsided days later, he was hospitalized on March 29 and remained in the hospital until April 14, when he tested negative for SARS-CoV-2 in two tests taken 24-hours apart.

About 4.5 months later, the man tested positive for the virus again. This time, his infection was caught during entry screening at a Hong Kong airport, as he returned from a trip to Spain, via the United Kingdom, on August 15. Though he had no symptoms, he was again hospitalized. Clinical data showed he had signs of an acute infection, but he remained asymptomatic throughout his time in the hospital.

Enlarge / Donald Trump gestures to Stephen Hahn, head of the FDA, at an earlier press conference. (credit: Drew Angerer )

Today, President Trump held a news conference to announce that the FDA has granted an Emergency Use Authorization for the treatment of COVID-19 cases using blood plasma from those formerly infected. The move comes despite significant uncertainty regarding just how effective this treatment is, and comes just days after Trump attacked the FDA for delaying its work as part of a plot to sabotage his re-election.

In the blood

Plasma is the liquid portion of the blood, which (among other things) contains antibodies. It has been used to treat other infections, as some antibodies can be capable of neutralizing the infecting pathogen—binding to the bacteria or virus in a way that prevents it from entering cells. Early studies have indicated that it's relatively common for those who have had a SARS-CoV-2 infection to generate antibodies that can neutralize the virus in lab tests, although the antibody response to the virus is also highly variable .

In the absence of any effective treatments, people started testing this "convalescent plasma" as early as March , and testing has been expanded as the pool of post-infected individuals has continued to grow. But so far, the evidence has been mixed. One of the largest studies, led by researchers at the Mayo Clinic and including over 35,000 patients, did see an effect , but it was a very mild one: mortality dropped from 11.9 percent in people who received plasma four days or more after starting treatment, compared with 8.7 percent if treatment was started earlier than that. But, critically, the study lacked a control group, leaving its authors talking about "signatures of efficacy," rather than actual evidence of efficacy.

Enlarge / Fishing vessels in Seattle. (credit: Getty | Art Seitz )

Hints of protective immunity against the pandemic coronavirus have surfaced in the wake of a recent COVID-19 outbreak that flooded the crew of a fishing vessel.

The coronavirus, SARS-CoV-2, infected 104 of the 122 people on board, about 85 percent, during a short voyage. But trawling through data collected before and after the ship set sail, researchers noted that the 18 spared from infection just happened to include the only three people on board that had potent, pre-existing immune responses against SARS-CoV-2. Specifically, the three sailors were the only ones found to have SARS-CoV-2 neutralizing antibodies, which are proteins that circulate in the blood and completely sink the infectious virus.

The numbers are small and the finding is not definitive. Additionally, the study appeared this month on a pre-print server , meaning it has not been published by a scientific journal or gone through peer review. Still, experts say the study was well done and significant for netting data that hint that potent, pre-existing immune responses from a past infection can indeed protect someone from catching the virus again.