CoVid19 is contracted through mocous membrames, mostly in the respiratory system. It spreads primarily in respiratory droplets, both larger, traveling up to six feet, and to a lesser extent arisonized dropplets which by their size carry a lower virus load and travel farther, up to about 26 feet. As a result, surface contact is possible but much less effective, and masks which directly address respiratory droplets are most effective. The viral load rises dramaticly in the first nine days during which most transmission occurs. Covid19 is most infectious about two days before symptoms begin and for five days afterward. Symptoms appear in up to fourteen days, if at all, with deaths, about 1.7% of infections, usually after about three weeks. Prolonged recovery is increasingly common as are neurological problems. Long Haul cases have remained in hospital for as much as six months, with long term damage apearing in more cases now.
Covid 19 (SARS-2) is no longer a single disease, with many variants. The Lambda strain is dominant in South America while the the Delta variant ia dominant in the U.S and U.K. As all viruses and bacteria, they continue changing, with the most successful becoming dominant. Any change that helps them avoid the immune system is n advantage for them.
While it mostly effects the lungs, it appears to be a blood disease causing clotting, and can attack almost all tissues from "covid toes" to the brain, and can cause permanent damage with reports of chronic lung and psychological problems increasing.
Testing is a contetious problem, expensive, inconveniont, and politicized. Testing where the results does not effect responce, as is with results taking over three days or those without symptoms and in quarentine is useless. To be useful to society, all positive tests need track and trace to prevent further spread.
Effective measures to limit contasion primarily address respiratory spread. "Deep Cleaning" is of limited efficacy while masks limit the spread of respiratory droplets from those with the virus and reduce the transmited viral load to those wearing a mask. The human imune system eliminates hundreds of potential diseases daily, but has problems with much larger exposures so masks are useful to both others and the wearer. That is why medical workers who are exposed to multiple high viral loads need N95 masks to reduce their immune systems exposure to the virus. A massive exposure can overwhelm a strong immune system. The vaccines are to prevent hospitalization and death by producing antibodies in the blood that prevent the coronavirus from taking root in the lungs and other organs. To prevent break through infections, the vaccines would have to produce more antibodies where the infection begins — in nasal secretions and saliva in the nose and the throat. The vaccines do produce antibodies there, probably enough to prevent infection with previous variants, but the Delta variant seems to replicate perhaps 1,000 times as much as its predecessors. That can overwhelm the immune defenses in the nose and the throat.
Epidemics require a chain of transmission and can continue only as long as it can reach new victims. Where the responce does not allow its transmission a disease is stopped. In Southern states like Alabama, Florida and Georgia, a spike in cases among those ages 20 to 39 led to a jump in cases nine days later among those ages 40 to 59, followed by a jump in cases 15 days later among those 60 and older. Transmission can be stopped by mask use, physical isolation from new victims (~14 days for CoVid19), or no susceptible hosts due to immune resopnce from imunization or previous infection. Iceland, New Zealand, and China have been notably successful while those unwilling to effectively respond long enough to stop it (US, Brazil, India) continue to suffer.
Viruses, like bacteria, have the ability to encrporate genetic material from others as well as mutate. Viruses change (mutate) over time. When a cell is infected with two viruses, i.e. a cold, genitic factors from both are replicated, aquiring the other's traits. One fear is co-morbidity with MERS or SARS while other corona viruses like the common cold would reduce vaccine effacacy. Evolution is inevitable, but the longer term trend is to less deadly and greater communicability, so anything causing rapid death tends to be replaced by those that keep the host alive and spreading that varient. There are thousands of variants, though most are not of greater concern. Names originally reflected where the variant was first identified, not where it came from. New varients of Covid-19 have been identified in the U.K., South Africa, New York, India, and California, with more to be found.
Vaccines are a means to inform the immune system about a pathogen. Parts of a pathogen are briefly presented to the immune system to identify it to enable a faster and stronger immune response. While the vaccine is only present for a couple of days, it is the immune system's recognition and developing antibodies that saves lives. A vaccine is judged by the accuracy, strength, and persistence of the immune response it provokes. Efficacy is defined as the probability of the immunized to contract the disease compared to one not immunized. Since part of the Covid19 strains bare some resemblance to the flus, the flu shots have shown some effect against it.
Those that need protection most are care staff, first responders, elderly with co-morbidity, those in institutional living situations such as nursing homes, prisons, and barricks, and the medically compromised since close proximity and time in contact lead to exposure to greater viral loads and exponential growth. Essential workers are next in priority. Those refusing immunization will continue to be potential vectors and victims. Covid19 will continue while there is a chain of transmission.
With over 220,000 deaths as of 9/22/2020, the U.S., which accounts for roughly 21% of all confirmed Covid-19 deaths around the world despite having only 4% of the world?s population, reporting about 61.09 deaths per 100,000 residents, the 11th most deaths per capita, more than the world's average per capita. It is one of the many signs that the Trump administration did a poorer job of controlling the virus than dozens of other governments around the world. With well over a half million deaths, areas with high vaccination rates have a dropping death rate while low vaccination rate areas have an again rising death rate.
What is not emphasized by media and politicians is the means of contagion. The viral load of exposure is critical. Just as in any battle, while a small assault can easily be stopped, the larger the attacking force, the more difficult the battle. Vaccinated and masked causes minimal exposure to an armed immune system, but an extreme exposure will be difficult, as is it for nurses treating covid patients. Lack of masking, crowds, length of exposure, and prevelance of infected people around you multiply exposure, hence increased infections.
We know how to stop Covid-19. If everyone wears a mask and observes physical distancing, with tracking and isolation, Covid-19 would cease to grow and the problem would end within six weeks, allowing economic safe re-opening. Elimination of control measures when the curve is bent is like stopping chemo when a cancer tumor stops getting bigger. Refusal to eliminate exposures insures covid19 will kill more people.