Evidence points to past COVID-19 infections producing strong immune responses which looks to be as effective as a vaccine.
By Neeraj Sood
Neeraj Sood is director of the COVID Initiative at the USC Schaeffer Center for Health Policy and Economics, firstname.lastname@example.org.
Abigail Horn is a research associate at the USC COVID-19 Pandemic Research Center, email@example.com.
David Conti, Special to CalMatters
David Conti is professor at the USC Department of Preventive Medicine, firstname.lastname@example.org.
President Joe Biden wants 100 million Americans vaccinated in 100 days, but scarce supplies and rollout snafus threaten to open a huge gap between ambition and achievement.
There is a smarter and easier way to attain the same public health benefits: Ask the millions of people who have already survived the coronavirus infection to step to the back of the line for vaccines.
Unfortunately, that is not the prevalent view of public health officials. Their chief rationale is that we cannot be sure how long natural immunity lasts.
But substantial evidence points to past infection producing a strong and sustained immune response which dramatically reduces the risk of symptomatic re-infection. Past infection looks to be as effective as a vaccine in providing protection.
Los Angeles County, the epicenter of the nation’s COVID-19 pandemic, illustrates what is at stake. More than 14,000 people have died, and recently about 10,000 tested positive each day. At the same time, scientists believe 1 in 3 of the county’s 10 million residents has already been infected by the virus – with a majority of those infections occurring within the last few months. The county simply can’t afford to misdirect vaccines to millions of individuals with recent past infections when inoculations are so critical to stemming the tide among the vulnerable.
We used the USC COVID-19 Model to show the public health consequences of different vaccination paths for Los Angeles during the first 100 days of the Biden administration. At its current rate of vaccinations, about 10,000 a day, Los Angeles County will save approximately 1,000 lives and avert 1,200 hospitalizations in the next 100 days compared to no vaccinations at all. By dramatically accelerating the vaccinations to 50,000 a day, we could double the public health benefits with an additional 1,000 lives saved and 1,400 hospitalizations avoided.
These same additional benefits can occur if the county convinced residents with past infections to postpone inoculations and increased vaccinations to only 15,000 a day. Even if we are only able to successfully convince half of those with previous infections to delay their vaccinations, the benefits would still be striking – the same number of lives can be saved at half the speed.
These projections are backed by a recent comprehensive analysis of post-infection immune response by leading immunologists that found that antibodies for the COVID-19 spike protein remained stable for more than six months, and that memory cells that trigger antibody production increased over time.
Despite millions of COVID-19 cases worldwide, only a handful of suspected reinfections have surfaced. A U.K.-based study that included 1,200 health care workers who had antibodies at the time the study began found no new symptomatic infections when tracking the workers over a 6-month period. A miniscule 3 out of the 1,200 workers developed asymptomatic COVID infection.
The science strongly indicates that someone who has had an infection and recovered is not likely to benefit immediately from a vaccination, especially compared to an unvaccinated person over 65. In the long run, it may be fine for individuals with past infections to double down and get vaccinated. Just not now.
Los Angeles County should ramp up antibody testing to try to identify as many people as possible who have had coronavirus infections, especially since many of them with asymptomatic disease might not have been diagnosed. Each person found to have had an infection is one less person who has to make an appointment for a vaccination.
Doctors and other health care professionals can counsel their patients who get an antibody test to postpone vaccination if the results come back positive. Then public health officials should launch a campaign telling people with past infections that they are OK to delay vaccination. What a welcome public health message that would be.