People who have recovered from COVID-19 and gained immunity to the disease could lose it again within months, a new study from the UK suggests. According to the research by a team from King’s College London, the novel coronavirus (SARS-CoV-2) could reinfect people year after year, much like common colds. Having studied the immune responses of more than 90 patients and healthcare workers at Guy’s and St Thomas’ NHS foundation trust, the researchers found that COVID-19 antibody levels peaked about three weeks after the onset of symptoms. [Related reading: Coronavirus: Immunity levels likely to be higher than antibody tests suggest] Blood tests revealed that while 60% of COVID-19 patients displayed a “potent” antibody response at the height of their battle with the disease, this figure fell to just 17% three months later. In some cases, antibody levels became undetectable. The findings of the study have implications when it comes to developing a COVID-19 vaccine, as well as achieving greater herd immunity. The bottom line is that if antibody levels drop over time and people are able to be reinfected seasonally, a vaccine would not actually provide any long-term benefits. Speaking about the findings of the study, Dr Katie Doores, lead author from King’s College London, said: “People are producing a reasonable antibody response to the virus, but it’s waning over a short period of time and depending on how high your peak is, that determines how long the antibodies are staying around.”
More people have immunity to coronavirus than antibody tests suggest, new research shows. The study from Sweden found that for every person who tested positive for antibodies — which are usually a strong indicator of whether someone has previously had an infection — two were found to have specific T-cells which identify and destroy infected cells. According to the research from the Karolinksa Institute in Sweden, even individuals who had mild or asymptomatic cases of COVID-19 had T-cells, despite testing negative for antibodies. The research is important because it could mean that more people than first thought have immunity to COVID-19. However, it is not yet clear whether this just protects the individual, or if it also stops them from passing on the infection to others. Prof Danny Altmann at Imperial College London described the study as “robust, impressive and thorough" and said it added to a growing body of evidence that "antibody testing alone underestimates immunity”. The results of the study are so new that they have not undergone peer review, nor been published in a scientific journal. Nevertheless, they can be seen as good news from a public health perspective as they indicate that public immunity to COVID-19 is likely a lot higher than first thought.
Research shows warmer temperatures do slow COVID-19 transmission (but not by much) Warmer temperatures have long been associated with reduced transmission rates of some respiratory viruses. It’s one of the reasons why flu tends to have a much larger impact during winter months. Therefore, it stands to reason that the spread of SARS-CoV-2 could also be slowed or even halted as countries start to experience warmer temperatures. Now, research seems to have confirmed what many people have thought. For the study, researchers from the Mount Auburn Hospital in Cambridge, Massachusetts looked at the effect of temperature, precipitation, and UV index on COVID-19 case rates in the United States from January 22, 2020 through April 3, 2020. They found the rate of COVID-19 incidence does decrease as temperatures get warmer, up until 52 degrees F. After that, virus transmission does not decrease significantly. Furthermore, while the overall impact remains modest, a higher UV index also assists in slowing the growth rate of new cases. Precipitation was not found to have any impact on the spread of the virus. The findings will comes as welcome news as many states in America see warmer weather easing in. However, the Centers for Disease Control and Prevention has warned that the COVID-19 pandemic could worsen again in the fall and winter as temperatures drop. [Related reading: What is COVID-19 antibody testing (and why is it useful?)]
There have been numerous reports recently about how both the European Union and the United States Food and Drug Administration (FDA) have now approved certain COVID-19 antibody tests. But what are these tests for and are they useful in the overall fight against the pandemic? An antibody test basically checks your blood for antibodies. These are made when your body fights an infection, like if you had COVID-19. The test isn’t actually looking for the infection itself, rather signs that your body has built a defense against it i.e. you had the infection and your body responded accordingly. One of the valuable outcomes of antibody tests is that they help us ascertain just how many people have potentially had the new coronavirus (SARS-CoV-2). This helps build a fuller picture of the virus’ spread, as well as calculate how many people there are out there who could still potentially get it. Such information could help in the development of strategies to safeguard communities and possibly allow for more freedom of movement. Antibody tests could also help identify individuals who have had COVID-19 and whose blood could be used to help those fighting the disease. [Related reading: Losing sleep over the COVID-19 outbreak? These 5 tips will help]