What happens if may 21st doesnt happen

It is clear now that summer does not uniformly stop the virus, but warm weather might make it easier to contain in temperate regions. In areas that will get colder in the second half of , experts think there is likely to be an increase in transmission. Many human respiratory viruses — influenza, other human coronaviruses and respiratory syncytial virus RSV — follow seasonal oscillations that lead to winter outbreaks, so it is likely that SARS-CoV-2 will follow suit.

Evidence suggests that dry winter air improves the stability and transmission of respiratory viruses 8 , and respiratory-tract immune defence might be impaired by inhaling dry air, she adds. In addition, in colder weather people are more likely to stay indoors, where virus transmission through droplets is a bigger risk, says Richard Neher, a computational biologist at the University of Basel in Switzerland.

The risk to adults who have already had COVID could be reduced, as with flu, but it would depend on how rapidly immunity to this coronavirus wears off, says Neher. To end the pandemic, the virus must either be eliminated worldwide — which most scientists agree is near-impossible because of how widespread it has become — or people must build up sufficient immunity through infections or a vaccine. Unfortunately, early surveys suggest there is a long way to go.

Estimates from antibody testing — which reveals whether someone has been exposed to the virus and made antibodies against it — indicate that only a small proportion of people have been infected, and disease modelling backs this up. Many vaccines provide protection for decades — such as those against measles or polio — whereas others, including whooping cough and influenza, wear off over time.

Likewise, some viral infections prompt lasting immunity, others a more transient response. One study 15 of recovering patients found that neutralizing antibodies persisted for up to 40 days after the start of infection; several other studies suggest that antibody levels dwindle after weeks or months.

Still, antibody production is not the only form of immune protection; memory B and T cells also defend against future encounters with the virus, and little is known so far about their role in SARS-CoV-2 infection. In that case, the virus would become endemic, says Pulliam.

If the virus induces short-term immunity — similar to two other human coronaviruses, OC43 and HKU1, for which immunity lasts about 40 weeks — then people can become reinfected and there could be annual outbreaks, the Harvard team suggests.

Yet these scenarios remain only guesses, because this pandemic has so far not followed the pattern of pandemic flu, says Osterholm. Mounting evidence suggests coronavirus is airborne — but health advice has not caught up.

In that case, even without a vaccine, it is possible that after a world-sweeping outbreak, the virus could burn itself out and disappear by However, if immunity is moderate, lasting about two years, then it might seem as if the virus has disappeared, but it could surge back as late as , the Harvard team found.

That forecast, however, does not take the development of effective vaccines into account. Even a vaccine providing incomplete protection would help by reducing the severity of the disease and preventing hospitalization, says Wu. Still, it will take months to make and distribute a successful vaccine. Regions with older populations could see disproportionally more cases in later stages of the epidemic, says Eggo; a mathematical model from her team, published in June 18 and based on data from six countries, suggests that the susceptibility to infection in children and people under 20 years old is approximately half that of older adults.

There is one thing that every country, city and community touched by the pandemic has in common. Rahmandad, H. Google Scholar. Nouvellet, P. Kennedy, D. PubMed Article Google Scholar. Santana-Cibrian, M. Hellewell, J. Lancet Glob. Health 8 , e—e Moriyama, M. Article Google Scholar. Neher, R. Swiss Med. Wkly , w Ly, H. When a chromosome is abnormal, it can cause health problems in the body. Abnormal chromosomes most often happen as a result of an error during cell division.

Chromosome abnormalities often happen due to one or more of these:. Meiosis my-OH-sis is the process in which sex cells divide and create new sex cells with half the number of chromosomes. Sperm and eggs are sex cells.

Meiosis is the start of the process of how a baby grows. Normally, meiosis causes each parent to give 23 chromosomes to a pregnancy. When a sperm fertilizes an egg, the union leads to a baby with 46 chromosomes. These problems can cause pregnancy loss. Or they can cause health problems in a child. There will always be things in life you can't control, so it's important to take control of the things that you can. Since the timing between COVID vaccine doses may impact the vaccine's effectiveness, it's important to take steps to help ensure you get your second dose on schedule.

March 1, - Katie McCallum. The recommended interval between the first and second dose is: Three weeks 21 days apart for Pfizer-BioNTech Four weeks 28 days apart for Moderna And while it's best to get your second dose on time Here's what you need to know if you miss your second COVID vaccine dose If a situation that's out of your control arises and causes you to miss your second dose, don't panic.

When it comes to getting your second dose on time, take steps to avoid the avoidable There will always be things in life you can't control, so it's important to take control of the things that you can. Here are three things you can do to help make sure you get your second dose on time: Check your calendar before scheduling your first dose. When making your appointment for your first dose, be sure that in three weeks' time Pfizer or four weeks' time Moderna you're actually available to come in for your second one.

You may not know which vaccine you're getting ahead of time, so be sure you're free and available both three and four weeks out. Leave your first appointment with your second appointment scheduled.