Herewith three items of pandemic news you may have missed recently: A particular risk of diabetes with Covid-19; worries of vaccine escape by the South African variant; and the many ideas floated for bolstering vaccine supply. Plus a frippery.
Ways to get more vaccine into more arms, quicker
As the pandemic rages unchecked in the US, the UK, and elsewhere just as the first vaccines come online, experts are casting about for ways to make scarce vaccine supplies stretch further and to get more people vaccinated sooner. Here are some of the strategies that have been promoted in recent days:
- Give just one shot instead of a two-shot regime. Michael Mina and Zeynep Tufekci boosted this idea in a NY Times editorial last month. We wrote about it here at the time.
- Delay the second shot. Ashish Jha and Robert Wachter penned an opinion piece in the Washington Post urging US authorities to go this route. One researcher urges hospitals simply to convert their vaccination program into a controlled trial of this idea. The UK has already decided on this strategy, based partly on a weak signal for the Oxford / AstraZeneca vaccine only, that its efficacy may improve with more time between shots. (There is no such data for Pfizer or Moderna.) Denmark has also decided to allow flexibility in timing the second shot; Germany is weighing the move.
- Cut the dose in half. The head of Operation Warp Speed, Moncef Slaoui, floated this idea. For the Moderna vaccine, there is (thin) data that in those 18 to 55 years old, two 50-μg doses were as effective as two shots of 100 μg each. This was not tested in those over 55, or in Pfizer’s trials.
- Allow mix-and-match vaccine doses. Britain will be permitting this, in effect doing a large-scale and uncontrolled experiment across their population.
There are two factors mitigating against all of the above ideas. First, the available data does not rigorously support any of them. Second, they would not help get vaccine into arms in the US any quicker, because the problems of last-mile vaccine distribution would continue to dominate.
Anthony Fauci has spoken against any alteration of the conditions that were rigorously tested in Phase III trials and authorized by the FDA: “The fact is we want to stick with what the science tells us.” A spokesman for Pfizer denigrated the idea of changing the dosing schedule. A Moderna spokesman said the company could not comment on altering dosing plans.
And now the FDA seems to have nailed the coffin shut on any such alterations, in the US at least.
Vaccines might be less efficacious against the SA variant
Much attention has been focused, rightly, on the UK variant of SARS-CoV-2, which has long been suspected of being more infectious; it now seems confirmed that the variant does result in higher viral loads upon infection (with the caution that this is a preprint, not peer-reviewed). There has been low-level worry that the variant might be somewhat more robust against the vaccines that have been authorized. For the UK variant in particular this worry is fading now.
However the similar, but distinct, variant that has arisen in South Africa presents more concern about (at least partial) immunological escape, according to the head of the British health service and virological experts.
It is fortunate that both Oxford / AstraZeneca and Johnson & Johnson are conducting Phase III studies in South Africa at the moment. Both expect to have real data soon on whether those who got shots while the new strain was circulating show any difference in rates of infection or disease. J & J says their study could read out as early as a few weeks from now.
A risk of diabetes and Covid-19
People with type 2 diabetes who contract Covid-19 are at increased risk of developing a rare but serious complication if they take one particular class of glucose-lowering drugs. According to research published in the journal The American Association of Clinical Endocrinologists Clinical Case Reports, patients who receive SGLT2i drugs (sodium-glucose cotransporter 2 inhibitors) might be at risk of a particular subset of diabetic ketoacidosis, known as euDKA, in which cells fail to metabolize glucose. The researchers hypothesized that the SARS-CoV-2 virus may be preferentially destroying insulin-producing cells on the pancreas; they also indicated suspicion that the overactive cytokines in some SARS-CoV-2 infections may be involved. Here is an accessible summary of the research.
Your frippery today is a marvelous little meditation on the meaning of magpies in a pandemic, by the writer Helen Macdonald, author of H Is For Hawk.