March 2021 Update: Vaccines and Variants
It was nearly a year ago when the lights dimmed on the world and our perspective was forever changed. For the luckiest among us, working at home has provided some level of comfort and control; but for so many, the pandemic has inflicted daily anxiety, fear, and even unspeakably tragic loss.
Today we face the dual reality of a mass vaccination effort on one hand and the impending surge in new cases from dangerous viral variants on the other. In these times of uncertainty, we maintain hope by staying informed. And of course our courageous healthcare professionals are dedicated to staying abreast of the latest Covid-19 research.
Vaccine Updates
Big picture: the vaccine news is VERY GOOD. The J&J vaccine (see vaccine information submitted to FDA here: https://www.fda.gov/media/146217/download) was tested in both the US and in South Africa, where the new variant is prevalent. And while there was less efficacy at preventing infections in South African patients, it still prevented severe infection. This is key. The Moderna and Pfizer vaccines have been shown to prevent severe infection in the dominant virus in the US, and now the J&J vaccine is "85 percent effective in preventing severe disease ACROSS ALL REGIONS STUDIED [MY EMPHASIS], 28 days after vaccination in all adults 18 years and older. Efficacy against severe disease increased over time with no cases in vaccinated participants reported after day 49." And the J&J vaccine "demonstrated complete protection against COVID-related hospitalization and death, 28 days post-vaccination. [There were a total of 7 deaths in the placebo arm and 0 deaths in the vaccine arm.] There was a clear effect of the vaccine on COVID-19 cases requiring medical intervention (hospitalization, ICU admission, mechanical ventilation, extracorporeal membrane oxygenation (ECMO)), with no reported cases among participants who had received the Janssen COVID-19 vaccine, 28 days post-vaccination." The J&J vaccine is expected to help drastically increase vaccinations in the US beginning in March, 2021, hopefully in time to significantly reduce exposure to the British variant of the virus and to reduce the risk of additional mutations by reducing overall transmission rates.
With the Novovax vaccine candidate, it is too early to say how well it works against the South African variant because the study was too small to see if it prevents severe illness. But no red flags on that front so far either. No severe disease was observed in the 15 individuals who became infected in the vaccinated group of a 4400 patient phase 2B study in S. Africa, but only 1 of 29 people who became infected in the placebo group had severe disease. In a much larger phase 3 study in the UK, the vaccine showed strong efficacy against infection from the British variant (>85%). The S. African study showed "60% efficacy (95% CI: 19.9 – 80.1) for the prevention of mild, moderate and severe COVID-19 disease...in the 94% of the study population that was HIV-negative [HIV infection is more prevalent in S. Africa]. Twenty-nine cases were observed in the placebo group and 15 in the vaccine group. One severe case occurred in the placebo group and all other cases were mild or moderate."
Viral Variants
It is expected that the British variant will predominate in the U.S. by the end of March. So far, it appears that the Pfizer, Moderna, J&J, and Astra Zeneca vaccines all maintain enough efficacy against this variant to protect the vast majority of individuals from severe illness or death. There is less certitude about the South African variant, though it still appears as though protection from severe illness is maintained even if there is reduced protection against becoming infected. The use of convalescent plasma and currently approved monoclonal antibodies is not likely to work well against the South African strain. However, new monoclonal antibodies can be developed quickly and convalescent plasma from those who have recovered from the South African variant may provide benefit to newly infected individuals. Data are needed to know for sure.
Getting back to Normal
Data are accumulating that those who have been vaccinated have a much lower risk of transmitting the virus to others. If these data are consistent across vaccines and viral variants, we will be able to stop wearing masks once the vast majority of people are vaccinated.
There are also new data showing that those who have recovered from Covid-19 only require one dose of Pfizer’s vaccine to vastly boost their existing immunity. If the same is found with the Moderna vaccine, the number of doses needed to vaccinate everyone in the U.S. will be significantly lower and will allow us to reach the desired herd immunity earlier in the year than expected. Stay tuned.