Health
Summer temperatures are rising – and so are cases of Covid-19
A young woman with Covid-19 symptoms
A trio of new variants – KP.3, KP.2 and LB.1 – are, together with the Centers for Disease Control and Prevention, causing a national increase in the number of Covid-19 cases. report an increase in test positivity (up 1.2%), emergency department visits (14.7%), hospitalizations (25%), and deaths (16.7%) in the most recent week. So many are wondering, “Why are we experiencing a summer surge and what can I do to stay safe?”
Why are Covid-19 cases increasing?
Between December 2023 and May 2024, the JN.1 variant – a descendant of the Omicron strain – was the leading cause of Covid-19 cases in the country. However, over the past two months, three new subvariants (called FLiRT by some) from JN.1 have emerged, now accounting for more than 70% of cases. These subvariants – KP.3, KP.2 and LB.1 – possess different mutations in the gene encoding the spike protein, which is the target of antibodies generated by Covid-19 vaccines.
These mutations allow KP.3, KP.2 and LB.1 to evade the immune system more effectively and potentially spread more efficiently. For those who received their last vaccination in 2023 or had a natural infection more than 6 months ago, their immune systems are less likely to fend off an infection from one of the new variants. This gap in specific immunity against KP.3, KP.2 and LB.1 contributes to the summer rise in Covid-19 cases.
A patient performing a Covid-19 rapid self-test at home.
Do the new Covid-19 subvariants cause more serious illness?
Fortunately, there is no evidence that infection with KP.3, KP.2 and LB.1 is associated with worse symptoms. Most infected individuals experience similar symptoms caused by previous Covid-19 variants, including sore throat, fever, cough, body aches and fatigue.
However, as the number of infections increases, so does the possibility that highly susceptible individuals – such as the elderly and those with weakened immune systems – could contract the virus and develop serious illness. These individuals may have difficulty breathing, which may require hospitalization.
Three steps to help you stay safe for the rest of 2024
Despite the increase in Covid-19 cases over the summer, there are steps you can take to protect yourself and those around you. First, if you feel sick, stay home and take a Covid-19 antigen test. If it is positive, you probably have Covid-19 and should stay away from others until your symptoms have cleared. If the home antigen test is negative, consider having a laboratory test for Covid-19. The good news is that both home antigen tests and laboratory tests should continue to detect the new subvariants.
Second, if you’re hosting a summer gathering, try to hold it outside. The virus spreads less quickly in well-ventilated outdoor areas. And if high temperatures force the party indoors, consider asking your guests to take a Covid-19 antigen test before arriving.
Finally, get an updated vaccine this fall. The Food and Drug Administration recently advised vaccine manufacturers to target the JN.1 lineage, and if possible the KP.2 subvariant, in the upcoming vaccine formulation. These new vaccines should be available this fall and will generate a more specific antibody response against recently circulating strains. Vaccination remains the best tool we have to prevent infections, and especially serious diseases.
