Can you have second wave of Covid-19 if first never ended?

WHEN Covid-19 first arrived in the United States, it hit New York and New Jersey particularly hard.
With the implementation of lockdown measures, mandated face masks, and other mitigation strategies there, cases in those states have substantially declined.
Meanwhile, Covid-19 cases have surged in many states in the south and west of the country throughout June and July including Florida, Texas, Arizona, California and others. Many Americans wonder what the coming months of the pandemic will look like in states where case rates are currently high, as well as states where the curve has been flattened.
What happens in the months ahead will largely depend on the actions of officials and other community members. While Covid-19 cases in northeastern states were falling this spring, experts there warned that a second wave of infections might hit in the fall.
At that point, experts didn’t know if the novel coronavirus would follow a seasonal pattern similar to common cold and flu viruses. Those viruses tend to be very active in late fall and winter, but cause few infections in warm months. The recent spike in cases in many southern and western states shows that the virus that causes Covid-19 does fine in hot conditions.
For example, sweltering temperatures in Arizona haven’t kept infection rates down. Whether the surge in cases there represents a “second wave” of infections or the continued cresting of the “first wave” doesn’t matter much.
COVID-19 VACCINE IS SAFE AND TRIGGERS IMMUNE RESPONSE IN HUMAN TRIAL: According to a new study, a Chinese phase II clinical trial of a Covid-19 vaccine candidate has shown that it is safe and induces an immune response.
With over 15 million confirmed cases of the new coronavirus, SARS-CoV-2, and more than 624,000 Covid-19 deaths globally, scientists around the world are competing against time to fast-track the development of new treatments to combat the disease.
Globally, scientists are developing about 250 candidate vaccines against SARS-CoV-2 infection. Of these, to date, at least 17 are under evaluation in clinical trials.
The authors of the recent study aimed to evaluate the safety and efficacy of a vaccine candidate called adenovirus type-5-vectored Covid-19 vaccine (Ad5-vectored Covid-19 vaccine).