The pandemic has taken several twists and turns and is far from over. With a focus on reinfections, this article examines some of the latest research and how it may shape our future.
1. The changing narrative on COVID vaccines
At the beginning of the pandemic, there was a simplistic view that if we got vaccinated or survive natural infection, we could stay protected from COVID-19 for the rest of our lives. Herd immunity advocates claimed they could “vaccinate themselves from the pandemic”. When the vaccines arrived in late 2020, the world was understandably jubilant. There were optimistic projections from vaccine makers presenting their best results – which was an impressive, albeit short-term, reduction in the incidence of symptomatic COVID-19.
However, the early mRNA vaccine studies that declared 95% efficacy did not consider asymptomatic infection, transmission, or longevity of protection.
Although vaccinations initially reduced the risk of infection, the protective effect quickly diminished after a few months – and more breakthrough infections were reported. Boosters arrived, but the problem didn’t go away. In fact, up to 65% of people who recently received an mRNA booster dose developed breakthrough infections. It was clear that these injectable or systemic vaccines did not provide adequate immunity at the virus’ portal of entry, the lining of the upper respiratory tract.
Vaccines had a more lasting effect in preventing the progression of a serious disease that thankfully has since remained stable. However, it must be noted that the total number of deaths in a region is directly related to the total number of infections. As public health measures were lifted in heavily vaccinated countries like Portugal, infection spread – and deaths rose.
If infection rates are not kept under control, death rates cannot be minimized.
2. What is the difference between breakthrough infection and reinfection?
Infections that occur in vaccinated people are called breakthrough infections. They are less likely to cause death compared to COVID-19, which occurs in an unvaccinated person.
When the virus infects someone who was previously infected, it is called reinfection. This can occur in both vaccinated and unvaccinated individuals.
3. Reinfections are trending now.
Two and a half years into the pandemic, repeated infections have become the norm. It’s not uncommon for doctors to encounter patients who have had multiple bouts of COVID-19.
In our recent study from India, we reported that at least 15% of people with COVID-19 have had COVID-19 for the second time or more, despite vaccination. Doctors practicing in different parts of India are already reporting that up to 40% of the COVID-19 patients they are currently treating actually have reinfections. This is confirmed by experiences from around the world.
Reinfection is therefore the trend term in 2022.
The ability of the rapidly evolving Omicron sublineages to escape immunity from previous vaccinations as well as from natural infections has exacerbated this problem. Therefore, reinfection within a few weeks is not uncommon. For example, US Secretary of Health Xavier Becerra recently had two bouts of COVID-19 within a month despite being fully vaccinated and boosted.
4. Different phases of the pandemic, different problems to deal with.
In 2020, surviving COVID-19 was a daunting challenge as there was no protection from vaccines or prior immunity. The mortality rate was relatively high; Millions of people lost their lives (mortality rate is defined as the probability of dying from infection). The deaths were not limited to vulnerable populations; many healthy young adults also succumbed.
In mid-2022, the equation looks different. The mortality rate has decreased and it is believed that this is mainly due to the effect of acquired immune memory.
On the other hand, the rate of infection has increased, which means a larger number of people are getting infected at the same time. As the virus adapted to evade immunity, reinfections became common. When this happened, there was a popular narrative that reinfections were a good thing and “helped build more immunity.”
All narratives have their proponents; This one was popular with people wanting to ditch masks and other public health measures. However, recent research has shown that Omicron is not a “natural booster” as some experts had previously claimed.
The question now is what the long-term outcomes are in people who get repeated infections.
5. Breakthrough infections are associated with long-term setbacks.
Researchers have studied the subsequent clinical course of those who survive a breakthrough infection.
Studies recently published in Nature have shown that those who survive a breakthrough infection are at an increased risk of dying for at least six months and at an increased risk of cardiovascular consequences for up to a year—compared to people without a breakthrough infection.
6. What are the potential downsides of repeat infection?
At the beginning of the pandemic, several experts had suggested that reinfections will be milder or asymptomatic. However, we now find that this is not always the case.
Recent US research on reinfections reported a cumulative effect, with worse outcomes in those who became infected more frequently.
In addition, there is an increased risk of post-acute sequelae or long COVID after reinfection.
Long COVID is a constellation of chronic symptoms lasting more than three months after the outbreak of COVID-19.
The excess risk of death and long COVID was lower in the vaccinated than in the unvaccinated.
7. How might this affect future public health policies?
With reduced mortality rates, the absolute number of adverse outcomes may seem insignificant at first glance. However, if reinfections occur in large parts of the population, the collective impact could be significant. As the limitations of COVID-19 vaccines are now well known, it is important to resort to evidence-based preventive public health strategies to reduce the spread of this virus in the community. Contrary to public perception, such strategies do not have to be restrictive as in the case of lockdowns. Examples include improving ventilation and allowing interior concealment in public spaces.
In this regard, it is worth noting that China, a country that has conducted extensive virus research, is pursuing a zero-COVID strategy – even after vaccinating its population. Although China has been criticized by western nations for its temporary lockdown measures, it seems clearly concerned that this virus will spread unchecked among its vast population.
8. Knowledge changes, and that’s a good thing
Knowledge of this new virus is evolving rapidly. Previous narratives based mostly on convenience and irrational optimism have been proven wrong. The virus seems to be here to stay, adapting to infect more people at ever shorter intervals. Unfortunately, although research is ongoing, we do not have a fully effective vaccine that can prevent infection.
In fact, there are several viruses against which there is still no vaccine or antiviral drug. That is the nature of these organisms.
However, public health interventions have reduced the disease burden of all infectious diseases. For example, cholera was fought by providing clean water instead of distributing antibiotics. Likewise, attention to air hygiene is key to COVID-19.
being cyclic disease, Ups and downs are to be expected with COVID-19, as well as several other viruses that infect humans. Particular caution is required during periods of ascent. This virus spreads through aerosols, which are basically tiny, weightless particles of liquid that float in the air for hours containing infectious virus particles. When these particles reach other people sharing the same space, the infection spreads. This is the rationale for avoiding unmasked mass gatherings in closed, poorly ventilated spaces.
In summary, we now live in a different world – one infested with a new virus that we cannot eliminate. Vaccines continue to protect against serious diseases but are not good at preventing infection or transmission. Reinfections are becoming more frequent and the intervals between infections are becoming shorter and shorter. Repeated infection with SARS-CoV2 appears to be associated with an increased long-term risk of death and cardiovascular consequences and must be avoided as much as possible. The virus continues to dominate, and optimistic predictions, even from renowned experts, are consistently proven wrong. Meaningful public health action must be taken before large sections of our population suffer the ill effects of repeated infections.
Attention to air hygiene is key
Cholera was fought by providing clean water rather than distributing antibiotics.
Repeated infection with SARS-CoV2 is associated with an increased long-term risk of death and cardiovascular consequences and must be avoided as much as possible.
Attention to air hygiene is key to COVID-19.
Although vaccines protect against serious illnesses, they are not very effective at preventing infection.
COVID-19 is not an ordinary cold; it can also affect the heart, brain, and blood vessels.
Scientific research aside, clear and effective public communication is an important part of fighting the pandemic.
Knowledge of this new virus is evolving rapidly, and previous narratives based mostly on convenience and irrational optimism have been proven wrong. The virus seems to be here to stay, adapting to infect more people at ever shorter intervals.