#102–Michael Osterholm, PhD: COVID-19—Challenges ahead & reasons for optimism and concern

KEYPOINTS

• 01

  This is a snapshot from 30 March 2020

  Michael Osterholm, the epidemiologist who directs the University of Minnesota's Center for Infectious Disease Research and Policy and worked on SARS in 2003 and MERS, was speaking as US cases surged. On 20 January his centre had published that this would be a worldwide pandemic, almost two months before it was declared one. Several of his figures were projections and have since been overtaken. Read them as reasoning, not results.

• 02

  Transmission would continue until much of the population was infected

  With each case infecting about 2–2.4 others, numbers double rapidly (1, 2, 4, 8, 16, 32…). Osterholm had 'every reason to believe' transmission wouldn't stop in any meaningful way until 50–70% of people were infected, unless it was suppressed. He also noted that past flu pandemics peaked about six months after the first cases.

• 03

  The scale arithmetic was sobering

  Sixty percent of a little over 300 million Americans is about 170–175 million infections. If 80% are mild, the remaining 20% have illness serious enough that many could need hospital care. Even 'only' 100,000 deaths would be a staggering, non-linear burden. New York was then averaging about 150 COVID deaths a day, against roughly 100 deaths a day from all causes in the past.

• 04

  Fatality rates are very sensitive to undercounted deaths

  His worked example: one death in 100 cases is 1%. Add 100 uncounted mild cases and it falls to 0.5%. But if those 100 extra cases come with 10 uncounted deaths, it becomes 11 in 200, over 5%. Missing deaths move the rate more than missing cases.

• 05

  Risk factors went beyond age

  Early Chinese data showed higher risk in men over 65, but about 70% of Chinese men over 65 smoke, compared with under 2% of women. New York was seeing more severe illness and deaths in people aged 25–50. Obesity, diabetes, kidney disease (about 700,000 Americans live with end-stage renal disease) and immunosuppression were concerns in a population he called highly vulnerable.

• 06

  Healthcare workers lacked protection

  Close to 4,000 health workers were infected in China and over 5,600 in Italy. 3M could make about 35 million N95 respirators a month. One New York hospital had used 2 million in a month, and Osterholm estimated the US would need 400 million or more for the first couple of months. When the CDC said to use surgical masks if N95s ran out, he warned many workers would risk their lives without proper protection.

• 07

  Supply chains were the hidden weakness

  Of 156 critical drugs used in intensive care, all are generic and about 85% are made outside the US. In 2003, China wasn't central to global manufacturing. By 2020, PCR machines and test reagents were impossible to buy because demand everywhere had soared. About 800,000 US tests had been done by then.

• 08

  A safe, effective vaccine would take time

  'I could make a vaccine tonight,' he said. The question is whether it is safe and effective. He expected one might work, perhaps needing boosters, but not before 2021. How T-cell and B-cell immunity work against coronaviruses was still uncertain.

• 09

  New antivirals are historically rare

  A review he cited found roughly 5,000 antiviral inhibitors proposed in the literature since about 1963, but only 90 approved over 55–60 years, about 40 of them for HIV. He was sceptical that repurposed drugs would be a quick fix.

• 10

  Some cautious good news on immunity

  He knew of no clear cases of reinfection after recovery, which hinted at some protection. He warned that it didn't prove durable immunity.

• 11

  Who gets infected shapes national fatality rates

  Korea's case fatality rate had just risen above 1%. Its large outbreak in a religious group with a median age of 43 kept the rate low at first. In Italy, Osterholm said, a large share of cases were in people over 80 with underlying health problems. Comparing countries without looking at who was infected is misleading.

• 12

  Long-term harm to survivors was unknown

  Attia raised the possibility of lingering myocarditis, kidney damage and lung fibrosis among survivors. Osterholm said those analyses hadn't been done yet. He likened the response to a boxer hit so hard he can only think about not getting hit again, not about counter-punching.