As a second COVID-19 wave hits Europe, many countries are implementing lockdown restrictions to flatten the curve. The second wave coincides with a pause in two vaccine clinical trials and the emergence of some documented cases of reinfection that may call into question early beliefs that a person who was infected with COVID-19 would be safe from catching the virus again.
Vaccine Clinical Trials Halted
Eli Lilly and Johnson & Johnson (J&J) both have paused their clinical COVID-19 vaccine trials this week. Since the J&J vaccine trial is a double blinded study, J&J has to wait for the Data Safety Monitoring Board (DSMB) — the entity that oversees the safety of such studies — to tell them if an unexplained illness seen in a trial participant received the drug or a placebo. If found to have taken the placebo, the trial will resume, but if not, it will take further investigation to figure out the root cause which will push the restart date. National Institutes of Health (NIH) halted the Eli Lilly COVID-19 antibody trial because one of the study groups was improving compared to the other, but they also must wait for DSMB to be told which group — the placebo or vaccine recipient — is showing signs of improvement. DSMB’s next meeting is October 26, when it can determine if the studies need to be stopped, modified or continued. Today, October 16, is the deadline for states to submit their plans to Centers for Disease Control and Prevention (CDC) for how they plan to distribute the COVID-19 vaccine when it is approved.
Europe’s Efforts to Curb Second Wave
Eighty percent of countries in Europe are seeing a rise in cases, making each country take necessary action to limit the second wave. Some parts of Germany are denying tourist reservations while others are requesting military support. Liverpool will be under tier-three lockdown restrictions — the strictest rules England imposes. French cities have elevated their alert to “maximum,” and many cities have imposed a nighttime curfew to limit social gathering congregations. Czech Republic, which currently has the highest illness rate in Europe, has closed schools and restaurants for the next three weeks.
Recovered COVID-19 Patients May Have Insufficient Immunity to Reinfection
A once-popular belief that having had a COVID-19 infection would prevent a person from catching the contagion again seems to be less grounded in reality than previously hoped. Documented cases of repeat infections with SARS-CoV-2 are emerging around the globe, including in the U.S. (here and here), Europe, Hong Kong, Brazil and possibly Qatar. One study examined such reports with the aim of separating instances of “true” reinfection from a continuation of the original infection and concluded that, at least in some cases, true reinfection is possible, despite the presence of SARS-CoV-2 IgG antibodies in the blood.
As reinfection cases grow in number, it is also becoming clear that in some patients, the second bout of infection leads to more severe symptoms than the first. This might be consistent with the trend observed in the still-ongoing clinical trials for vaccine candidates, where the frequency of fever and other adverse side-effects increased after the second dose (and with larger doses).
What factors determine the course of infection, recovery, and resistance to subsequent re-infections? Only careful research can provide reliable and actionable answers. And research does progress remarkably rapidly. For example, the “wish-list” suggestions published by scientists in June 2020 (e.g., for genetic sequencing of the virus strains involved in infections and reinfections) have since become a reality and are already yielding new and useful knowledge. Nevertheless, we are still on that journey of discovery. There is still much to be learned about the human immune system’s responses to SARS-CoV-2.