The result of the spiking numbers s an interesting psak by Rav Chaim Kanievsky.

Until now we have heard of individual rosh yeshivas, community rabbis, and Hassidic leaders instructing their students and followers to not get tested, so as to not put the yeshiva or community at risk of being shut down or forced into closure because of too many Corona infections. This approach has been widely criticized, but it has not gone away. 

In Professor Roni Gimzu's approach to fighting Corona, known as the traffic light model (approved by the Corona Cabinet this past week), cities will be classified as red, orange, yellow or green, depending on the levels of Corona spreading in the city. Depending on the classification, the city will be treated accordingly with different restrictions, obviously with red having the strictest restrictions. One of the lesser known aspects of the traffic light model is that if a city has too little testing, it gets tagged as red, even with a low number of corona positives - so the approach of "not testing" to avoid detection and classification should not be rewarded.

Rav Chaim Kanievsky today paskened that yeshiva, referring specifically to yeshiva gedolas with dormitories, should no longer get their students tested. Rav Kanievsky explained that the testing causes tremendous bittul torah, with thousands of talmidim who are not at risk being forced into quarantine. Rav Kanievsky has added that this applies to dormitory yeshivas who should stay "closed" until after Yom Kippur, with nobody coming in or out and the boys staying in yeshiva throughout the zman until Yom Kippur including all the Shabbosses (shabbatot). Essentially he is telling them to quarantine all together in the yeshiva without testing, instead of testing and some boys being sent home or to Corona Hotels. Obviously staff members and rebbeim who are in a high risk category should all be careful to keep their distance from the students.

sources: Kikar, Actualic, Hamechadesh

I get his opinion, especially if he is telling them to all basically quarantine in yeshiva anyway. t almost seems harmless, unless you think the yeshivas dont really have a way to control it and stop boys from leaving or coming back. Some probably do and some probably don't,

The bigger question is how this will affect the nation and the decisions to be mad eon further restrictions. I am worried that with no testing in yeshivas, it will have an adverse affect on the decision to be made regarding a closure fo the holidays. They will decide that the numbers are no longer reliable and there is too much unknown. Without a closure all those untested yeshiva boys, many of whom likely have corona or will contract it soon while locked up together  will come home after Yom Kippur and on Sukkos will infect their grandparents and uncles and aunts and other at risk family members. 

I am concerned that this decision by Rav Kanievsky will almost gaurantee a government decision for a full closure over the holidays.