Vaccination rates are high in the U.S., but that doesn’t mean we can let up just yet.ByChia-Yi Hou | Apr. 8, 2021https://imasdk.googleapis.com/js/core/bridge3.450.0_en.html#goog_205855657700:00 of 01:06Volume 20%
Story at a glance
- Although cases may be decreasing around the country, coronavirus cases are still relatively high in some areas and are spiking in Michigan.
- Issues like partial vaccination of a population could come into play.
- Inequitable access to vaccines remains a concern, especially globally.
With many states in the U.S. relaxing restrictions and the weather turning warmer, it may seem like we are coming out of the pandemic. However, with cases recently spiking in Michigan and concerning cases and death rates elsewhere in the world such as Brazil, it’s a reminder that we are not yet out of the woods.
Last year, we looked at the different ways the pandemic could come to an end. Now with vaccines and variants on the scene, here’s a revisit to the topic and what we know now.
There could be issues getting the pandemic under control if we’re stuck at low levels of vaccination or partial vaccination. The way that immunity works at the population level means that, depending on the pathogen’s transmission rates, immunization at a low percentage of the total population would not be enough to prevent some transmission and cases to occur.
The ideal percentage vaccinated varies by disease, but for COVID-19 some experts estimate it to be at least 70 percent, although this may change as more data become available. If in the U.S. the vaccination rate slows down before we reach a high enough percentage, that could mean that we get small outbreaks and pockets of COVID cases around the country where the vaccination rates are lowest.
Then there’s the issue of partial vaccination on the individual level. People who have gotten one dose are partially protected after a few weeks, but they may potentially interact with people who haven’t had any shots or also have had one shot. Vaccination does not totally prevent infection, as far as we know, and people who are vaccinated may be able to transmit the virus to others even if that has a very low probability of happening.
So with people around the country at varying stages of vaccination and immunity, that could lead to a patchwork of COVID cases that could allow the virus to remain in the population. Research from the Centers for Disease Control and Prevention suggests that even one dose of either the Pfizer or Moderna vaccines provide a good amount of protection, but more data is needed to show this is happening on a national scale.
Once domestic travel picks up again, this complicates the situation further. Then a single location is no longer a simple population on its own. It has individuals entering and leaving the population. For example, this could mean that even if New York is doing well with vaccinating its population, unvaccinated people who are traveling to New York could continue to bring in the coronavirus and add to local outbreaks. The focus on each state’s progress would be less informative and the focus would need to be on national progress.
WHAT YOU NEED TO KNOW ABOUT CORONAVIRUS RIGHT NOW
Experts have not yet determined what a potential vaccination schedule might be for the coronavirus. Experts are also studying whether these existing vaccines protect against the coronavirus variants that have cropped up in the U.S. and around the world.
People who participated in the clinical trials for the coronavirus vaccines are receiving booster shots six months or more after their initial doses. An initial study from Pfizer and BioNTech suggests that its vaccine maintains 90 percent efficacy at the half year mark post second dose. If it turns out that the current vaccines are less effective at protecting against the coronavirus variants, the vaccine developers may need to produce adapted versions.
We are still learning about how long immunity lasts and how well the vaccines protect against the coronavirus variants. It may come to be that this time next year everyone will need a booster shot to maintain immunity against the virus. If, or when, that time comes, the urgency to get a booster shot may not be there for many people, and that could lead to varying levels of immunity within the population. That could leave many people with higher susceptibility to the coronavirus than others, which could boost infection rates and lead to more cases. This could mean that small outbreaks may move through and be sustained in the population if enough people are susceptible.
Inequitable access to vaccines
An issue that has become prominent around the world is inequitable access to vaccines, and one reason for that is intellectual property rights. The companies that developed the vaccines that are currently approved for emergency use are not willing to give up patent rights and share the methods for making their vaccines with other companies. This could slow down the long-term vaccination roll out for countries that were not able to secure doses before.
In addition, some wealthier countries prepaid for more than they needed because it wasn’t certain yet which vaccines would get emergency use approval. Other countries were lost in the free for all to buy up vaccines and are relying on a global effort called COVAX to get the shots. Many lower-income countries will be the last ones on the list to get vaccines, some not expecting any shipments until 2022 and some experts suggesting that many would not get any until 2024 if current behavior by high-income countries continues.
COVAX has purchased about 1 billion doses and could reserve 900 million more. It aims to immunize 20 percent of the people most vulnerable to the virus in low-income countries. But that falls short of getting most of the population in these countries vaccinated to stop the spread of the virus.
This presents a problem for all of us. While international travel is limited, as people start moving around more this increases the risk of arriving in a place where there are high numbers of cases or where many people are not yet vaccinated. Similar to the problem with people traveling domestically making it important to focus on national progress, this would make it important to focus on global vaccination progress.
Local outbreaks and epidemics
For all these reasons, it’s likely that there will continue to be local outbreaks and smaller epidemics around the country and in other parts of the world. The global pandemic may diminish to the point where it may not be a crisis any longer, but there could continue to be cases for a long time to come. We may stop calling it a pandemic at some point, but the novel coronavirus may still be around for a while after that.
Whether it is a pandemic or not depends on the global effects. On the other hand, COVID-19 could become endemic to humans, meaning that it will circulate in our populations indefinitely similarly to influenza. That does not mean that we will see death rates like we have in the past year. As we adapt to the coronavirus and it adapts to us, we could move towards a sort of equilibrium where the virus proliferates in our bodies but doesn’t kill us as easily.
These are all still unknowns at this point. As experts gather more data on how the vaccination roll outs have affected transmission of the virus and the number of cases, we’ll understand more about these dynamics.
For up-to-date information about COVID-19, check the websites of the Centers for Disease Control and Prevention and the World Health Organization. For updated global case counts, check this page maintained by Johns Hopkins University.
You can follow Chia-Yi Hou on Twitter.
WHAT YOU NEED TO KNOW ABOUT CORONAVIRUS RIGHT NOW