Since the beginning of the Covid-19 pandemic, variants of the original Covid-19 strain have been considered a danger to the effective control of the pandemic. In the last six months, three particular variants have evolved, including the UK (B.1.1.7), South Africa (B1.351), and Brazil (P.1) variants. These are especially concerning due to their enhanced transmissibility and rapid progression to dominant strain status in their locales. The last variant, P.1, may be the most frightening in that it reportedly can create viral loads in infected indivduals that are ten times the level that other strains possess.
Within the last month, the US has become known for having its own home-grown Covid-19 variants. One variant called B.1.5.2.6 was originally described in November in New York City and has been found in over 585 cases in the last two weeks of February. Currently, this strain is estimated to be present in over 25% of cases in New York City. While overall cases from this strain have been observed mainly in the New York/New Jersey area, there are already documented cases with this variant in 14 other states. Notably, the US performs genetic typing on very few Covid-19 cases so the variant is probably involved in far more than the captured number of Covid-19 cases.
A separate US strain with important implications has concurrently been described. Epidemiologists have noted the emergence of a strain in California called B.1.427/29 (referred to previously as “20C” or “L452R”). This strain contains three mutations affecting the spike protein including one called the L452R mutation of the RBD (receptor binding domain) and may augment the ability of the virus to attach to the host mucosa. This California strain has been shown to be potentially resistant to the host’s neutralizing antibodies and may be therefore more likely to escape antibodies from previous infection or vaccination. Other observations have shown that this strain may be more lethal than other strains in the California area. This last observation is quite concerning if it is indeed valid but the concept needs to be confirmed in larger populations.
Researchers at USCF have suggested that the California strain may become the dominant strain in that region by the end of next month. Previously, many thought the UK variant would be the dominant strain in the US by the end of March. However, in a “nightmare scenario” straight out of Hollywood, a highly respected researcher worries that the two strains could meet in the same person, exchange genetic material, and emerge as an even more dangerous strain.
Evidence that these new strains are creating significant havoc to Covid-19 control in the US will be evident in the next few weeks. Absolute numbers of Covid-19 cases were declining rapidly but have suddenly hit a plateau. If cases now start to ascend as the weather starts to warm up, epidemiologists can be rightfully fearful that the variants will have assumed a more prominent role in American Covid-19 cases. Broader genetic typing will confirm this supposition and needs to be monitored by public health officials.
Increased variants in the US population could pose a host of devastating sequellae for the American public. Case numbers could escalate and thwart many reopening ambitions. Surveillance testing would need to increase. Some vaccinated individuals could become infected with these new strains although the lethality from the strains may be variable. Everyone including vaccinated people would also need to continue masking and social distancing. They potentially would have to be included in exposure and travel quarantines. Booster shots might be needed earlier than the fall to control the pandemic fully for some of the vaccinated individuals. Symptom monitoring for public spaces such as offices and venues will continue to be necessary for public safety in the foreseeable future.