Immunity after an Omicron infection develops relatively quickly, often within days to a couple of weeks for initial protection, but the strength and duration vary, with studies showing reduced protection against reinfection over time, especially with newer Omicron subvariants, meaning hybrid immunity (infection plus vaccination) offers the best, longer-lasting defense.
Can you get COVID twice in a month? This is very unlikely, but in theory it's possible. People at highest risk for getting a reinfection so quickly are those who have health conditions that weaken their immune system.
This community-based cross-sectional study included 12,789 highly vaccinated adults primarily infected with Omicron, with 7.8% of them developed long COVID within one year, and 5.1% had persistent long COVID (LC) at 1-year after infection. The risk of long COVID increased with reinfection in a dose-dependent manner.
COVID-19 infection—even mild cases—can cause substantial long-term changes in the immune system that may be implicated in long COVID, concludes a new observational study by Medical University of Vienna (MUV) researchers published in Allergy.
Researchers in Japan have pinpointed a biological cause of Long COVID brain fog using advanced PET brain imaging. They discovered widespread increases in AMPA receptor density linked to cognitive impairment and inflammation.
However, studies have shown the virus can last about two days on some fabrics. It's unlikely you'll get COVID from your bedding, though. Just be sure to wash your bedding if you or anyone in your household has COVID, and disinfect your home's surfaces. How long COVID can live on other surfaces?
An important finding, say the researchers, is that despite reinfection, previous infection still conferred “robust and durable protection against severe COVID-19 with no observed waning in this protection”.
Can you be contagious after a negative COVID test? If you test negative with a PCR test, you are likely not contagious. But if you test negative with an at-home test, the answer will depend in part “on whether the negative COVID test is at the beginning of feeling sick or on the way to recovery,” Mina says.
Many people gain protection against another infection (reinfection) for several months. But this natural immunity lessens as time passes. If you have a weakened immune system, your body may not build up effective natural immunity after an infection. So, you may get sick again sooner than others would.
But an unlucky group has been hit with reinfection after reinfection. “I've seen a few patients with five infections,” said Dr. Grace McComsey, vice dean for clinical and translational research at Case Western University. “Sadly, they were immunized and they still got Covid five times.”
What is COVID rebound? COVID rebound is “typically described as a recurrence of signs or symptoms or a new positive viral test result after initial recovery from COVID-19,” according to the CDC .
As the virus evolves, new variants with the ability to evade your existing immunity can appear. This can increase your risk of reinfection. Reinfection can occur as early as several weeks after a previous infection, although this is rare.
Lower protection with Omicron
Effectiveness rapidly declined after the previous infection, dropping from 81.3% at 3 to 6 months to 59.8% in the next 3 months and 27.5% in the 3 months after that. Protection was negligible after 1 year. Efficacy was 59.5% in the first year, plummeting to 4.8% thereafter.
Since August 24, 2025, a total of 40,804 COVID-19 detections have been reported (from 592,373 tests). A total of 31,610 laboratory-confirmed COVID-19 detections with age information have been reported.
7 Steps to Take After a Virus Has Hit Your Home
One of the most talked-about emerging strains this year is the NB.1.8.1 variant, part of the Omicron family. While current evidence suggests it is not more severe than previous variants, it is spreading quickly and causing concern due to its highly contagious nature.
Can you reinfect yourself with items such as a toothbrush or a reusable water bottle? Consider this information. Toothbrushes — It is recommended that you replace your toothbrush after an illness due to the chance of becoming reinfected, but professionals agree this isn't typically true for viruses.
Cleaning is an important first step to make sure you remove most germs from surfaces in your home. Using household cleaners that contain soap or detergent will remove germs and dirt on surfaces. Cleaning alone removes most harmful viruses or bacteria from surfaces.
Cardboard. The New England Journal of Medicine recently published a study that tested how long the Coronavirus can remain stable on different kinds of surfaces within a controlled laboratory setting. They found that it was still detectable on cardboard for up to 24 hours.
KP. 2 is one of several variants being referred to as “FLiRT variants,” named after the technical names for their mutations. The prevalence of these variants comes at a critical time, when experts are deciding how to formulate the fall COVID vaccine.
Multisystem inflammatory syndrome (MIS) is a rare but serious condition associated with SARS-CoV-2, the virus that causes COVID-19, in which different internal and external body parts become inflamed, including: heart. lungs. kidneys.
What are the most common symptoms of long COVID?